Methodology, Module, Terminal, and System Enabling Scheduled Operation of a Radio Frequency Identification (Rfid) Subsystem and a Wireless Communication Subsystem

ABSTRACT

The invention relates to a method for scheduling communications over a wireless communication subsystem and a radio frequency identification (RFID) communication subsystem, said method comprising determining one or more periods of activity of the wireless communication subsystem; deriving one or more periods of non-activity on the basis of the one or more determined periods of activity; synchronizing an operation of the radio frequency identification (RFID) communication subsystem with the one or more periods of non-activity; and triggering the operation of the radio frequency identification (RFID) communication subsystem in accordance with the one or more derived periods of non-activity to enable substantially concurrent communications operation of the wireless communication subsystem and the radio frequency identification (RFID) communication subsystem.

The present invention relates to short-range communication systems.Particularly the present invention relates to quasi simultaneousoperation of radio frequency identification (RFID) reader interface incellular communication terminals. More particularly, the presentinvention relates to a time- and frequency-aligned operation of radiofrequency identification (RFID) reader interface with respect tocellular communication.

Radio frequency identification (RFID) technology relates basically tothe field of local communication technology and more particularly localcommunication technology involving electromagnetic and/or electrostaticcoupling technology. Electromagnetic and/or electrostatic coupling isimplemented in the radio frequency (RF) portion of the electromagneticspectrum, using for example radio frequency identification (RFID)technology, which primarily includes radio frequency identification(RFID) transponders also denoted as radio frequency identification(RFID) tags and radio frequency identification (RFID) reader interfacesfor radio frequency transponders also denoted for simplicity as radiofrequency identification (RFID) readers.

In the near future, an increasing amount of different radio technologieswill be integrated to mobile terminals. Expanding range of differentapplications drives need and requirement to provide radio accessmethodologies with different data rate, range, robustness, andperformance specifically adapted to application environments and usecases, respectively. As a consequence to the multi-radio scenariosproblems in interoperability of the multi-radio enabled mobile terminalswill become a challenge in development.

Radio frequency identification (RFID) technology is one of the recentarrivals in the terminal integration radio frequency identification(RFID) communication enables new usage paradigms, e.g. pairing ofdevices, exchanging security keys, or obtaining product information bytouching items provided with radio frequency identification (RFID) tagswith radio frequency identification (RFID) communication enabledterminal. Typically, the operation range between the radio frequencyidentification (RFID) tag and radio frequency identification (RFID)reader interface in consumer applications is considered to be only a fewcentimeters.

Actually, there have already been product releases in radio frequencyidentification (RFID) readers integrated in mobile phones. Currentimplementations are based on Near Field Communications (NFC) technologythat operates on 13.56 MHz. The communication in that technology isobtained by inductive coupling and therefore it requires rather largecoil antennas both in the reader and tag. Furthermore, inductivecoupling has its limitations when it comes to the range of the radioconnection. Typically the maximum range at 13.56 MHz with reasonableexcitation current and antenna sizes is about 1-2 m.

The limited range of radio frequency identification (RFID) systems at13.56 MHz has increased the interest in supply chain management andlogistics application arena towards higher frequencies, namely UHF(ultra high frequency) and microwave frequencies. At UH frequencies(around 868 MHz in Europe and 915 MHz in United States in accordancewith the frequency allocation) the achievable range in industrial andprofessional fixed installations is up to ten meters, which allowscompletely new applications compared to 13.56 MHz. The operation ofradio frequency identification (RFID) communication at UHF and microwavefrequencies is based on backscattering, i.e. the reader (interrogator)generates an excitation/interrogation signal and the radio frequencyidentification (RFID) tag (RFID transponder) alters its antennaimpedance according to a specified, data dependent pattern.

Currently, the most significant standardization forum at the UHF band isthe EPCglobal that is leading the development of industry-drivenstandards for the Electronic Product Code (EPC) to support the use ofRadio Frequency Identification (RFID) in today's fast-moving,information rich trading networks. The shorter-term target is to replacebar codes in pallets, and in long term also in packages and someindividual products. If those targets come true, users will get productinformation or pointers to more detailed information to their radiofrequency identification (RFID) communication enabled terminals just bytouching an item, which is provided with an EPCglobal conforming radiofrequency identification (RFID) transponder.

The excitation power generated in a radio frequency identification(RFID) reader subsystem is reasonably high, from about 100 mW ofconsumer applications related to mobile terminal to several watts usedin professional fixed applications. The used frequency allocations forUHF radio frequency identification (RFID) band are the 868 MHz ISM bandin Europe and the 915 MHz band in United States. Obviously, the usedfrequencies are close to the used cellular frequencies, which are 880MHz-915 MHz as well as 925 MHz-960 MHz in Europe and 824 MHz-849 MHz aswell as 869 MHz-894 MHz in United States for mobile station cellulartransmitter and receiver, respectively. Due to the quite powerful radiofrequency identification (RFID) excitation signal the radio frequencyidentification (RFID) reader subsystem emits, there can be severeinterference caused to an operating cellular transceiver located in thesame terminal due to the imperfect nature of the radio frequencyidentification (RFID) excitation signal and limited rejection of the RFfilters. In practice, the radio frequency identification (RFID) readerantenna and the cellular antenna might be only a couple of centimetersspaced from each other, and thus the coupling loss might be somethingabout 10-20 dB. Considering a RF power level of the radio frequencyidentification (RFID) reader subsystem of about 20 dBm (corresponding toabout 100 mW), there might be a 0 dBm signal seen in the antenna port ofthe cellular transceiver. The cellular antenna and balun with theirfrequency dependency as well as the front end RF filter reject theinterference in some extent, but the resulting signal level is stillhigh enough to drastically interfere or in some situations even blockthe desired cellular signal. In an extreme case when a maximumintegration benefit is searched for, the cellular radio and the radiofrequency identification (RFID) reader might use the same antenna sinceoperating frequencies of those systems are typically close to each otherand hence one antenna could serve both systems.

It is an object of the present invention to provide a methodology andmeans to enable coordinated usage of both radio frequency identification(RFID) subsystem and wireless communication subsystem. In particular,the coexistence considered applies to a cellular communication subsystemand a radio frequency identification (RFID) subsystem integrated to thesame terminal device. The radio frequency identification (RFID)subsystem causes interference by means of raised noised floor to anyoperating wireless communication subsystem in that mobile terminal.

The object of the present invention is solved by the features of theaccompanying independent claims.

According to an aspect of the present invention, a method for schedulingcommunications over a wireless communication subsystem and a radiofrequency identification (RFID) communication subsystem is provided. Oneor more periods of activity of the wireless communication subsystem aredetermined. On the basis of the one or more determined periods ofactivity, one or more periods of non-activity are derived. An operationof the radio frequency identification (RFID) communication subsystem issynchronized with the one or more periods of non-activity. Then, theoperation of the radio frequency identification (RFID) communicationsubsystem is triggered in accordance with the one or more derivedperiods of non-activity such that substantially concurrentcommunications operation of the wireless communication subsystem and theradio frequency identification (RFID) communication subsystem isenabled.

According to another aspect of the present invention, a computer programproduct is provided, which enables Listen-Before-Talk measurement toallow identifying of one or more unoccupied RF sub-bands applicable forradio frequency identification (RFID) communication operable with aradio frequency identification (RFID) reader subsystem. The computerprogram product comprises program code sections for carrying out thesteps of the method according to an aforementioned embodiment of theinvention, when the program is run on a computer, a terminal, a networkdevice, a mobile terminal, a mobile communication enabled terminal or anapplication specific integrated circuit. The computer program productcomprising the code sections may be stored on a computer readablymedium. Alternatively, an application specific integrated circuit (ASIC)may implement one or more instructions that are adapted to realize theaforementioned steps of the method of an aforementioned embodiment ofthe invention, i.e. equivalent with the aforementioned computer programproduct.

According to another aspect of the present invention, a schedulingmodule arranged for scheduling communications over a wirelesscommunication subsystem and a radio frequency identification (RFID)communication subsystem is provided. The scheduling module is operablewith the wireless communication subsystem and the radio frequencyidentification (RFID) communication subsystem and the scheduling moduleis arranged for determining one or more periods of activity of thewireless communication subsystem and deriving one or more periods ofnon-activity on the basis of the one or more determined periods ofactivity. The scheduling module is synchronized with the one or moreperiods of non-activity. A trigger signal is generated by the schedulingmodule and supplied to the radio frequency identification (RFID)communication subsystem to trigger an operation of the radio frequencyidentification (RFID) communication subsystem in accordance with the oneor more derived periods of non-activity to enable substantiallyconcurrent communications operation of the wireless communicationsubsystem and the radio frequency identification (RFID) communicationsubsystem.

According to another aspect of the present invention, a terminal deviceenabled for scheduled communications over a wireless communicationsubsystem and a radio frequency identification (RFID) communicationsubsystem of the terminal device is provided. The terminal devicecomprises a scheduling module operable with the wireless communicationsubsystem and the radio frequency identification (RFID) communicationsubsystem. The scheduling module is arranged for determining one or moreperiods of activity of the wireless communication subsystem and derivingone or more periods of non-activity on the basis of the one or moredetermined periods of activity. The scheduling module is synchronizedwith the one or more periods of non-activity. A trigger signal isgenerated by the scheduling module and supplied to the radio frequencyidentification (RFID) communication subsystem to trigger an operation ofthe radio frequency identification (RFID) communication subsystem inaccordance with the one or more derived periods of non-activity toenable substantially concurrent communications operation of the wirelesscommunication subsystem and the radio frequency identification (RFID)communication subsystem.

According to another aspect of the present invention, a system isprovided, which enables scheduled communications over a cellularcommunication subsystem and a radio frequency identification (RFID)communication subsystem comprised by the system. The system furthercomprises a scheduling module operable with the cellular communicationsubsystem and the radio frequency identification (RFID) communicationsubsystem. The scheduling module is arranged for determining one or moreperiods of activity of the wireless communication subsystem and derivingone or more periods of non-activity on the basis of the one or moredetermined periods of activity. The scheduling module is synchronizedwith the one or more periods of non-activity. A trigger signal isgenerated by the scheduling module and supplied to the radio frequencyidentification (RFID) communication subsystem to trigger an operation ofthe radio frequency identification (RFID) communication subsystem inaccordance with the one or more derived periods of non-activity toenable substantially concurrent communications operation of the wirelesscommunication subsystem and the radio frequency identification (RFID)communication subsystem.

For a better understanding of the present invention and to understandhow the same may be brought into effect reference will now be made, byway of illustration only, to the accompanying drawings, in which:

FIG. 1 illustrates schematically principle block diagrams depictingtypical components of a radio frequency identification (RFID)transponder and a radio frequency identification (RFID) readersubsystem;

FIG. 2 a illustrates schematically a principle block diagram of aportable cellular terminal enabled for radio frequency identification(RFID) communication according to an embodiment of the presentinvention;

FIG. 2 b illustrate schematically a principle block diagram of a radiofrequency identification (RFID) reader subsystem according to anembodiment of the present invention;

FIGS. 3 a to 3 c illustrate schematically principle block diagrams ofdifferent implementations of the portable cellular terminal enabled forradio frequency identification (RFID) communication according to anembodiment of the present invention;

FIGS. 4 a to 4 d illustrate schematically operational sequencesapplicable with a scheduling mechanism to enable coordinated radiofrequency identification (RFID) communication and cellular communicationaccording to an embodiment of the present invention;

FIG. 5 a illustrates schematically an exemplary GSM/EDGE activity timingdiagram and radio frequency identification (RFID) communication activitytiming diagram according to an embodiment of the present invention;

FIG. 5 b (1)-(4) illustrate schematically an exemplary WCDMA compressedframe mode communication time diagram according to an embodiment of thepresent invention;

FIG. 6 a illustrates more detailed the exemplary GSM/EDGE Activitytiming diagram and radio frequency identification (RFID) communicationactivity timing diagram of FIG. 5 a according to an embodiment of thepresent invention;

FIG. 6 b illustrates schematically a power-up and power-down radiofrequency envelope of a radio frequency identification (RFID) readersubsystem according to an embodiment of the present invention;

FIG. 6 c illustrate schematically a pulse interval encoding of a data-0and data-1 symbol used in radio frequency identification (RFID)communication according to an embodiment of the present invention;

FIG. 6 d illustrate schematically link timing diagram of a radiofrequency identification (RFID) communication between a radio frequencyidentification (RFID) reader subsystem and a radio frequencyidentification (RFID) transponder according to an embodiment of thepresent invention; and

FIG. 6 e illustrates schematically a sequence of radio frequencyidentification (RFID) communication processes and operation states of aradio frequency identification (RFID) transponder according to anembodiment of the present invention.

Throughout the description below, same and/or equal components will bereferred by the same reference numerals.

In the following, the concept of the present invention will be describedwith reference to a cellular communication subsystem, which inparticular supports GSM, GSM/GPRS, GSM/EDGE, cdma2000, and/or UMTScellular communication. Moreover, the radio frequency identification(RFID) communication will be described with reference to Ultra-HighFrequency (UHF) radio frequency identification (RFID) communication,which in particular supports EPCglobal standard. It should be noted thatthe aforementioned specifications of the cellular communicationsubsystem as well as the radio frequency identification (RFID) readersubsystem are given for the sake of illustration. The invention shouldbe understood as not being limited thereto.

Originally, radio frequency identification (RFID) technology has beendeveloped and introduced for electronic article surveillance, articlemanagement purposes, and logistics primarily for replacing bar codeidentification labels, which are used for article management purposesand logistics up to now. A typical implementation of a state of the artradio frequency identification (RFID) transponder is shown with respectto FIG. 1. A typical radio frequency identification (RFID) transpondermodule 10 includes conventionally an electronic circuit, depictedexemplary as transponder logic 12, with data storage capacity, depictedherein as transponder memory 13, and a radio frequency (RF) interface11, which couples an antenna 14 to the transponder logic 12 The radiofrequency identification (RFID) transponders are typically accommodatedin small containers, particularly mounted to the item to be tagged bythe means of adhesive. Depending on the requirements made on envisagedapplications of the radio frequency identification (RFID) transponders(i.e. the data transmission rate, energy of the interrogation,transmission range etc.) different types are provided fordata/information transmission at different radio frequencies within arange from several 10-100 kHz to some GHz (e.g. 134 kHz, 13.56 MHz, 860MHz-928 MHz etc; only for illustration). Two main classes of radiofrequency identification (RFID) transponders can be distinguished.Passive radio frequency identification (RFID) transponders are activatedand energized by radio frequency identification (RFID) readers, whichgenerate an excitation or interrogation signal, for example a radiofrequency (RF) signal at a predefined frequency. Active radio frequencyidentification (RFID) transponders comprise their own power supplies(not shown) such as batteries or accumulators for energizing.

Upon activation of a radio frequency identification (RFID) transponderby the means of a radio frequency identification (RFID) reader module20, the informational contents stored in the transponder memory 13 aremodulated onto a radio frequency (RF) signal (i.e. the interrogation RFsignal), which is emitted by the antenna 14 of the radio frequencyidentification (RFID) transponder module 10 to be detected and receivedby the radio frequency identification (RFID) reader module 20. Moreparticularly, in the case of a passive radio frequency identification(RFID) transponder (i.e., having no local power source), the radiofrequency identification (RFID) transponder is conventionally energizedby a time-varying electromagnetic radio frequency (RF) signal/wavegenerated by the interrogating radio frequency identification (RFID)reader. When the radio frequency (RF) field passes through the antennaassociated with the radio frequency identification (RFID) transponder10, a voltage is generated across the antenna. This voltage is used toenergize the radio frequency identification (RFID) transponder 10, andenables back transmission of information from the radio frequencyidentification (RFID) transponder to the radio frequency identification(RFID) reader, which is sometimes referred to as back-scattering.

Typical state of the art radio frequency identification (RFID)transponders correspond to radio frequency identification (RFID)standards such as the ISO 14443 type A standard, the Mifare standard,Near Field Communication (NFC) standard, and/or the EPCglobal standard.

In accordance with the application purpose of a radio frequencyidentification (RFID) transponder, the information or data stored in thetransponder memory 13 may be either hard-coded or soft-coded. Hard-codedmeans that the information or data stored in the transponder memory 13is predetermined and unmodifiable. Soft-coded means that the informationor data stored in the transponder memory 13 is configurable by anexternal entity. The configuration of the transponder memory 13 may beperformed by a radio frequency (RF) signal received via the antenna 14or may be performed via a configuration interface (not shown), whichallows access to the transponder memory 13.

A radio frequency identification (RFID) reader module 20 typicallycomprises a RF interface 21, a reader logic 22, and a data interface 23.The data interface 23 is conventionally connected with a host systemsuch as a portable terminal, which, inter alia, on the one handexercises control over the operation of the radio frequencyidentification (RFID) reader 20 by the means of instructions transmittedfrom the host to the reader logic 22 via the data interface 23 and onthe other hand receives data provided by the reader logic 22 via thedata interface 23. Upon instruction to operate, the reader logic 22initiates the RF interface 21 to generate the excitation/interrogationsignal to be emitted via the antenna 24 coupled to the RF interface 21of the radio frequency identification (RFID) reader module 20. In casethat a radio frequency identification (RFID) transponder such as a radiofrequency identification (RFID) transponder module 10 is within thecoverage area of the excitation/interrogation signal, the radiofrequency identification (RFID) transponder is energized and a modulatedRF signal (back-scatter RF signal) is received therefrom. Particularly,the modulated RF signal carries the data stored in the transpondermemory 13 modulated onto the excitation/interrogation RF signal. Themodulated RF signal is coupled into the antenna 24, demodulated by theRF interface 21, and supplied to the reader logic 22, which is thenresponsible to obtain the data from the demodulated signal. Finally thedata obtained from the received modulated RF signal is provided via thedata interface to the host system.

FIG. 2 shows a schematic block illustration of components of a portableelectronic terminal 100 in an exemplar form of a mobile/cellulartelephone terminal. The portable electronic terminal 100 exemplarilyrepresents any kind of processing terminal or device employable with thepresent invention. It should be understood that the present invention isneither limited to the illustrated portable electronic terminal 100 norto any other specific kind of processing terminal or device.

As aforementioned, the illustrated portable electronic terminal 100 isexemplarily carried out as cellular communication enabled portable userterminal. In particular, the portable electronic terminal 100 isembodied as a processor-based or micro-controller based systemcomprising a central processing unit (CPU) and a mobile processing unit(MPU) 110, respectively, a data and application storage 120, cellularcommunication means including cellular radio frequency interface (I/F)180 with correspondingly adapted RF antenna (181) and subscriberidentification module (SIM) 185, user interface input/output meansincluding typically audio input/output (I/O) means 140 (conventionally amicrophone and a loudspeaker), keys, keypad and/or keyboard with keyinput controller (Ctrl) 130 and a display with display controller (Ctrl)150, and a (local) wireless and/or wired data interface (I/F) 160.

The operation of the portable electronic terminal 100 is controlled bythe central processing unit (CPU)/mobile processing unit (MPU) 110typically on the basis of an operating system or basic controllingapplication, which controls the functions, features and functionality ofthe portable electronic terminal 100 by offering their usage to the userthereof. The display and display controller (Ctrl) 150 are typicallycontrolled by the processing unit (CPU/MPU) 110 and provide informationfor the user including especially a (graphical) user interface (UI)allowing the user to make use of the functions, features andfunctionality of the portable electronic terminal 100. The keypad andkeypad controller (Ctrl) 130 are provided to enable the user inputtinginformation.

The information input via the keypad is conventionally supplied by thekeypad controller (Ctrl) to the processing unit (CPU/MPU) 110, which maybe instructed and/or controlled in accordance with the inputinformation. The audio input/output (I/O) means 140 includes at least aspeaker for reproducing an audio signal and a microphone for recordingan audio signal. The processing unit (CPU/MPU) 110 can controlconversion of audio data to audio output signals and the conversion ofaudio input signals into audio data, where for instance the audio datahave a suitable format for transmission and storing. The audio signalconversion of digital audio to audio signals and vice versa isconventionally supported by digital-to-analog and analog-to-digitalcircuitry e.g. implemented on the basis of a digital signal processor(DSP, not shown).

The keypad operable by the user for input comprises for instancealphanumeric keys and telephony specific keys such as known from ITU-Tkeypads, one or more soft keys having context specific inputfunctionalities, a scroll-key (up/down and/or right/left and/or anycombination thereof for moving a cursor in the display or browsingthrough the user interface (UI), a four-way button, an eight-way button,a joystick or/and a like controller.

The portable electronic terminal 100 according to a specific embodimentillustrated in FIG. 2 includes the cellular communication subsystem 180coupled to the radio frequency antenna (181) and operable with thesubscriber identification module (SIM) 185. The cellular communicationsubsystem 180 is arranged as a cellular transceiver to receive signalsfrom the cellular antenna, decodes the signals, demodulates them, andalso reduces them to the base band frequency. The cellular communicationsubsystem 180 provides for an over-the-air interface, which serves inconjunction with the subscriber identification module (SIM) 185 forcellular communications with a corresponding base station (BS), basestation controller, nodeB, and the like of a radio access network (RAN)of a public land mobile network (PLMN). The output of the cellularcommunication subsystem 180 thus consists of a stream of data that mayrequire further processing by the processing unit (CPU/MPU) 110. Thecellular communication subsystem 180 arranged as a cellular transceiveris also adapted to receive data from the processing unit (CPU/MPU) 110,which is to be transmitted via the over-the-air interface to the basestation (BS) of the radio access network (RAN) (not shown). Therefore,the cellular communication subsystem 180 encodes, modulates andup-converts the data embodying signals to the radio frequency, which isto be used for over-the-air transmissions. The antenna (outlined) of theportable electronic terminal 100 then transmits the resulting radiofrequency signals to the corresponding base station (BS) of the radioaccess network (RAN) of the public land mobile network (PLMN). Thecellular communication subsystem 180 preferably supports a 2^(nd)Generation digital cellular network such as GSM (Global System forMobile Communications) which may be enabled for GPRS (General PacketRadio Service) and/or EDGE (Enhanced Data for GSM Evolution; 2.5Generation), a 3^(rd) generation digital cellular network such as anyCDMA (Code Division Multiple Access) System including especially UMTS(Universal Mobile Telecommunications System) and cdma2000 System, and/orany similar, related, or future (3.5 Generation, 4^(th) Generation)standards for cellular telephony.

The wireless and/or wired data interface (I/F) 160 is depictedexemplarily and should be understood as representing one or more datainterfaces, which may be provided in addition to or as an alternative ofthe above described cellular communication subsystem 180 implemented inthe exemplary portable electronic terminal 100. A large number ofwireless communication standards are available today. For instance, theportable electronic terminal 100 may include one or more wirelessinterfaces operating in accordance with any IEEE 802.xx standard, Wi-Fistandard, WiMAX standard, any Bluetooth standard (1.0, 1.1, 1.2,2.0+EDR, LE), ZigBee (for wireless personal area networks (WPANs)),Infra-Red Data Access (IRDA), Wireless USB (Universal Serial Bus),and/or any other currently available standards and/or any futurewireless data communication standards such as UWB (Ultra-Wideband).

Moreover, the data interface (I/F) 160 should also be understood asrepresenting one or more data interfaces including in particular wireddata interfaces implemented in the exemplary portable electronicterminal 100. Such a wired interface may support wire-based networkssuch as Ethernet LAN (Local Area Network), PSTN (Public SwitchedTelephone Network), DSL (Digital Subscriber Line), and/or otheravailable as well as future standards. The data interface (I/F) 160 mayalso represent any data interface including any proprietaryserial/parallel interface, a universal serial bus (USB) interface, aFirewire interface (according to any IEEE 1394/1394a/1394b etc.standard), a memory bus interface including ATAPI (Advanced TechnologyAttachment Packet Interface) conform bus, a MMC (MultiMediaCard)interface, a SD (SecureData) card interface, Flash card interface andthe like.

The portable electronic terminal 100 according to an embodiment of thepresent invention comprises a radio frequency identification (RFID)reader subsystem 190 coupled to a RF antenna 194. Reference should begiven to FIG. 1 and the aforementioned description thereof, whichillustrates the basic implementation and operation of a radio frequencyidentification (RFID) reader module. The radio frequency identification(RFID) reader subsystem 190 may be included in the terminal 100, fixelyconnected to the terminal 100, or detachably coupled to the terminal100. Moreover, the radio frequency identification (RFID) readersubsystem 190 may be provided with a functional cover of the portableelectronic terminal 100, which is detachably mounted to the portableelectronic terminal 100. Preferably the radio frequency identification(RFID) reader subsystem 190 may be integrated in such a detachablefunctional cover. In accordance with the inventive concept of thepresent invention, a scheduler 200 is comprised by the terminal 100. Thescheduler 200 is connected to the terminal 100, the cellular interface180, and/or the radio frequency identification (RFID) reader subsystem190. Details about the specific implementation of the radio frequencyidentification (RFID) reader subsystem 190 and the scheduler 200 arepresented in the following.

The components and modules illustrated in FIG. 2 may be integrated inthe portable electronic terminal 100 as separate, individual modules, orin any combination thereof. Preferably, one or more components andmodules of the portable electronic terminal 100 may be integrated withthe processing unit (CPU/MPU) forming a system on a chip (SoC). Suchsystem on a chip (SoC) integrates preferably all components of acomputer system into a single chip. A SoC may contain digital, analog,mixed-signal, and also often radio-frequency functions. A typicalapplication is in the area of embedded systems and portable systems,which are constricted especially to size and power consumptionconstraints. Such a typical SoC consists of a number of integratedcircuits that perform different tasks. These may include one or morecomponents comprising microprocessor (CPU/MPU), memory (RAM: randomaccess memory, ROM: read-only memory), one or more UARTs (universalasynchronous receiver-transmitter), one or more serial/parallel/networkports, DMA (direct memory access) controller chips, GPU (graphicprocessing unit), DSP (digital signal processor) etc. The recentimprovements in semiconductor technology have allowed VLSI(Very-Large-Scale Integration) integrated circuits to grow incomplexity, making it possible to integrate all components of a systemin a single chip.

Typical applications operable with the portable electronic terminal 100comprise beneath the basic applications enabling the data and/or voicecommunication functionality a contact managing application, a calendarapplication, a multimedia player application, a WEB/WAP browsingapplication, and/or a messaging application supporting for instanceShort Message Services (SMS), Multimedia Message Services (MMS), and/oremail services. Modern portable electronic terminals are programmable;i.e. such terminals implement programming interfaces and executionlayers, which enable any user or programmer to create and installapplications operable with the portable electronic terminal 100. Atoday's well established device-independent programming language isJAVA, which is available in a specific version adapted to thefunctionalities and requirements of mobile device designate as JAVAMicro Edition (ME). For enabling execution of application programscreated on the basis of JAVA ME the portable electronic terminal 100implements a JAVA MIDP (Mobile Information Device Profile), whichdefines an interface between a JAVA ME application program, also knownas a JAVA MIDlet, and the portable electronic terminal 100. The JAVAMIDP (Mobile Information Device Profile) provides an executionenvironment with a virtual JAVA engine arranged to execute the JAVAMiDlets. However, it should be understood that the present invention isnot limited to JAVA ME programming language and JAVA MiDlets; otherprogramming languages especially proprietary programming languages areapplicable with the present invention.

The principle concept of the present invention addresses the coexistenceof a radio frequency identification (RFID) reader 190 and a cellularradio interface 180 and their concurrent operation. The concept of thepresent invention will be described with reference to UHF radiofrequency identification (RFID) communication, especially EPCglobalconform standard for radio frequency identification (RFID)communication. Moreover, the concept of the present invention will alsobe described with reference a cellular radio interface 180 especiallysupporting GSM, GSM/EDGE, WCDMA and/or cdma2000. Nevertheless it shouldbe noted that the present invention is not limited to those specificembodiments. Those skilled in the art will appreciate on the basis ofthe description that the concept of the present invention is likewiseapplicable with any other radio frequency identification (RFID)communication standard and wireless communication standard (includingespecially any other cellular communication standards and wirelessnetwork communication standards).

As aforementioned, there are allocated specific frequency bands for UHFradio frequency identification (RFID) communication:

UHF RFID 868 ISM band (Europe): 868-870 MHz (at max. 500 mW); and UHFRFID 915 band (USA): 902-928 MHz (at max 4 W).

According to the different cellular standards various frequency bandsare allocated for cellular communication. The following table lists aselection of frequency bands used; the table is not exhaustive. Forlater reference, commonly accepted abbreviations for the differentfrequency bands are denoted.

Uplink RF Band Downlink RF Band System Designation [MHz] [MHz] GSM 900(Europe): 890-915 935-960 GSM 1800 (Europe): 1710-1785 1805-1880 GSM 850(USA): 824-849 869-894 GSM 1900 (USA): 1850-1910 1930-1990 cdma2000(USA): 1850-1910 1930-1990 WCDMA 2100 (Europe): 1920-1980 2110-2170

The skilled reader will appreciate that the frequency bands used by UHFradio frequency identification (RFID) communication and cellularcommunications do not overlap. Hence, the concurrent operation ofcellular as well as UHF radio frequency identification (RFID)communication could be obtained by utilizing RF components of highestquality, at least theoretically. In practice, such highest qualitycomponents would be bulky and expensive. Hence, from cost and size pointof view, a solution with ability to schedule operations of those radiospreferably in time domain would be preferable.

The excitation/interrogation signal, i.e. the downlink signal of an UHFradio frequency identification (RFID) reader is typically an amplitudeor phase modulated carrier. The power of the signal is dependent on theapplication, but it might be several Watts in industrial applicationsand possibly a couple of hundreds of milliwatts in portable terminalrelated applications. Typically, the radio frequency identification(RFID) reader emits its excitation signal based on user action (e.g.input signal detected upon pressing a button by the user) or applicationrequest (e.g. generated by an application for instance upon timerexpiry). During the exchange of data between the radio frequencyidentification (RFTD) reader and the radio frequency identification(RFID) transponder, the radio frequency identification (RFID) readercontinuously emits the carrier signal to keep the radio frequencyidentification (RFID) transponder energized (cf. aforementioneddescription). The emission of a powerful carrier in an uncoordinatedmanner during any cellular radio operation would be detrimental to thecellular radio performance, and therefore this kind of situation shouldbe avoided.

According to an embodiment of the present invention the portableterminal 100 has a control entity, which enables the radio frequencyidentification (RFID) reader operation only in coordination with anycellular radio transceiver operation such that preferably a concurrentor simultaneous operation of both radio frequency identification (RFID)communication and cellular communication is obtainable.

Herein, it should be understood that concurrent and/or simultaneouscommunication operations may be operated on physical level (low layerlevel) time multiplexed, where the time multiplexing is transparent forthe user such that substantially concurrent and/or simultaneouscommunication operations are experienced.

In the first basic case the control entity, the scheduler 200 comprisedby the portable terminal 100, checks whether the cellular radio is(totally) turned off before the schedulers allows the radio frequencyidentification (RFID) reader to start its interrogation andcommunication. This first basic approach is quite simple, since rampingup the cellular operation takes some time in a case where the cellularconnection is needed right away after the radio frequency identification(RFID) communication activity.

In a more sophisticated approach, the radio frequency identification(RFID) communication activity is scheduled to take place during theinactive periods of the cellular operation. The same principle can beapplied to different states of the terminal. When the terminal is notattached to the cellular network, the radio frequency identification(RFID) reading situation is quite straight forward. Irrespective of thecellular system in question, in the idle/standby operation mode theterminal listens to paging messages, performs measurements related tointra-cell power levels and related to adjacent cell (inter-cell) powerlevels and availability of other systems, and sends random accessmessages, when required. The required activity in this state is quitelow to ensure long battery life, and hence there is plenty of time forradio frequency identification (RFID) communication activity. In theactive state, the terminal is either engaged to a voice call or dataexchange through a packet connection. This state, and also statespreceding and following the active state (e.g. ready state in GPRS),requires a significant amount of activity, and hence the time availablefor radio frequency identification (RFID) reading operation is quitelimited. For example, there is only (8−2)×0.577 ms≈3.5 ms time (notethat according to GSM time frame structure, each frame comprises eighttime slots) to accomplish radio frequency identification (RFID) readingoperations during an active GSM call, since most probably both cellulartransmission (1 time slot out of 8 time slots) and reception (1 timeslot) would be disturbed by radio frequency identification (RFID)reading activity at these time slots.

Consequently, according to the present invention the scheduler 200establishes an interface between a radio frequency identification (RFID)subsystem, which is herein embodied as radio frequency identification(RFID) reader subsystem 190, and the host system, which is hereinembodied as portable terminal 100. By the means of a scheduleralgorithm, which is preferably implemented on the basis of the scheduler200 with the help of hardware and/or software implementation, theconcurrent multi-radio operation in the aforementioned manner isenabled. The control over the radio frequency identification (RFID)subsystem operation is exercised by the host system (i.e. portableterminal 100) via the scheduler 200. To enable the control, the radiofrequency identification (RFID) subsystem (i.e. radio frequencyidentification (RFID) reader subsystem 190) may be provided with(digital I/O) trigger signal terminal 196 and watchdog logic.

With reference to FIG. 2 b, a radio frequency identification (RFID)subsystem on the basis of the radio frequency identification (RFID)reader subsystem 190 according to an embodiment of the present inventionis illustrated. As aforementioned, the radio frequency identification(RFID) reader subsystem 190 includes the typical components required forradio frequency identification (RFID) reader operation, namely a datainterface (I/F) 191 coupled to the host system (i.e. the portableterminal 100), a reader logic 192 for instance implemented on the basisof a micro-controller (μC), and a radio frequency (RF) interface 193coupled to a RF antenna 194. A watchdog logic 195 according to anembodiment of the present invention is arranged to enablecontrollability over the operation of the radio frequency identification(RFID) reader subsystem 190. The watchdog logic 195 may be integratedinto the reader logic or implemented separately. The watchdog logic 195may be supplied with a trigger signal from the host system (portableterminal 100) through a trigger terminal 196. The trigger signal isprovided by the scheduler 200 and generated in accordance with thescheduling algorithm.

The scheduling algorithm will be described in more detail below. Itshould be noted that the data interface (I/F) 191 connected to the hostsystem may be likewise arranged to receive configuration data andinstructions from the host system. The configuration data andinstructions allow defining details of the radio frequencyidentification (RFID) reader operation.

With reference to FIGS. 3 a to 3 c schematic diagrams of the majorcomponents allowing concurrent communication operations according to anembodiment of the present invention are illustrated.

The host system is operated by the user via a user interface (UI) 30, bythe means of which the user is allowed to access the functions of thehost system (e.g. the portable terminal 100). In view of the multi-radiooperation, the control exercised by the user via the user interface (UI)30 is performed through the controlling scheduler 200, which isinterposed between the cellular communication subsystem 180 and theradio frequency identification (RFID) reader subsystem 190. Thearrangement of the controlling scheduler 200 enables on the one side toobtain information about the actual radio communication operationsperformed via the cellular communication subsystem 180 as well as theradio frequency identification (RFID) reader subsystem 190 and on theother side to supply this obtained information and user inputs via theuser interface to the scheduling algorithm to enable the concurrentmulti-radio operation. In analogy, the control may be also exercised byan application 35, which is enabled controlling operation of thecellular communication subsystem 180 and the radio frequencyidentification (RFID) reader subsystem 190 through the controllingscheduler 200.

In detail, FIGS. 3 a to 3 c depict different antenna arrangementsincluding separate antennas 181 and 194 for the cellular communicationsubsystem 180 as well as the radio frequency identification (RFID)reader subsystem 190, a common antenna 182 coupled to both the cellularcommunication subsystem 180 and the radio frequency identification(RFID) reader subsystem 190 and a common antenna 182 coupled to the bothsubsystems 180, 190 via a switch 196. The common antenna 182 ispreferably a multi-frequency antenna, i.e. an antenna whichcharacteristics is adapted to several frequency bands. Such antennas arefor instance known in the field of dual and tri-band GSM terminals. Withreference to the implementation shown in FIG. 3 b, frequency band-passfilters (not shown) may be included into the signal path between antenna183 and the cellular communication subsystem 180 as well as the radiofrequency identification (RFID) reader subsystem 190 to separate RFsignals received by the antenna 183 such that frequencies of differentfrequency bands are supplied to the respective subsystem 180 or 190 inaccordance with the corresponding operation radio frequency bands. Withreference to the implementation shown in FIG. 3 c, a RF switch 196 isarranged to selectively couple the common antenna 182 to either of thesubsystems 180 and 190 in accordance with a time-aligned operationthereof. The RF switch 196 may be also implemented as a tunableband-pass filter circuitry. The signal for adjusting the tunableband-pass filter circuitry is supplied by the controlling scheduler 200.The signal separation proposed with reference to FIG. 3 c isadvantageous to RF circuitries of the cellular communication subsystem180 as well as the radio frequency identification (RFID) readersubsystem 190 since RF signals generated by one of the subsystems 180 or190 is not applied to the respective other one. In particular, theimplementation schematically illustrated in FIG. 3 c drives therequirement to schedule of the operation of the both subsystems 180 and190 in a time-aligned way. The common antenna 182 is selectively coupledto either of the subsystems 180 and 190. RF signal reception and RFsignal emission is either operable with either the cellularcommunication subsystem 180 or the radio frequency identification (RFID)reader subsystem 190, respectively.

The scheduler 200 may be arranged separately from the subsystems 180 and190, the scheduler 200 may be implemented together with the subsystems180 and 190 within a multi-radio communication subsystem, the scheduler200 may be implemented on the basis of one or more individual hardwareand/or software components and/or these scheduler components may be partof the terminal 100, the cellular communication subsystems 180 or theradio frequency identification (RFID) reader subsystem 190.

With reference to FIG. 4 a, an overall operation sequence of thescheduling algorithm according to an embodiment of the present inventionis illustrated. The operational sequence although depicted as a linearsequence should be understood as the core of a monitoring loopalgorithm, which is performed repeatedly in time. Based on themonitoring loop operation and the ability to obtain information aboutthe actual cellular operation frequency of the cellular communicationsubsystem 180, control over the radio frequency identification (RFID)reader subsystem 190 is exercised.

The scheduler 200 is preferably arranged to perform following operationswhen a user or an application requests the operation of the radiofrequency identification (RFID) reader subsystem 190.

In operation S100, the actual frequency band is determined at which thecellular communication subsystem 180 is currently operated. Thedetermination of the actual frequency band is performed independentlywhether the portable terminal operates currently in idle operation stateor active operation state. It should be noted that the terms idleoperation state, standby operation state, and active operation stateaddress to the operation relating to the operativeness of the cellularcommunication subsystem 180. In particular, idle/standby operation statedesignates an operation mode of the cellular communication subsystem180, where paging and measurement operations are performed but there isnot performed any data or voice communication through the cellularcommunication subsystem 180. In active operation state, data and/orvoice communication is performed via the cellular communicationsubsystem 180 with the Radio Access Network (RAN) of the Public LandMobile Network (PLMN), to which the cellular communication subsystem issubscribed.

In operation S110, it is checked whether the cellular communicationsubsystem 180 is currently operated at the 850 MHz or 900 MHz frequencyband (cf. frequency band definition given above). In case the cellularinterface operates at another frequency band which is adequately spacedapart from the UH frequency used by the radio frequency identification(RFID) reader subsystem 190, it can be assumed that a concurrentoperation of both the cellular communication subsystem 180 and the radiofrequency identification (RFID) reader subsystem 190 is operable withdiminished interference. The operational sequence branches to operationS220, where the concurrent operation is allowed. However, it should benoted that the allowance of a concurrent operation is merely possible inconjunction with a RF circuitry implementation which enables theconcurrent reception and emission of RF signals at different frequenciessuch as depicted by the way of illustration with respect to FIGS. 3 aand 3 b. Principally, a RF circuitry implementation as embodied withreference to FIG. 3 c does not enable such a concurrent operation. Insuch a case reference should be given to the time-alignment, which willbe descried below with reference to operations S160 to S230.

In practice, almost all cellular terminals, which are on the markedtoday and which will be on the market in future, are at least multi-bandterminals or preferably, multi-band, multi-system terminals. Typicalcellular GSM conform terminals support GSM 900/1800 communication or GSM850/1800/1900 communication. Moreover, latest cellular multi-systemterminals support GSM 900/1800/1900 communication and WCDMA 2100 (UMTS)communication. The same applies to cellular terminals supporting CDMA,e.g. cdma2000 enabled cellular terminals supporting CDMA 850/1900communication and are examples of available frequency combinations. Notethat the cellular terminals specified above are described for the way ofillustration; the present invention is not limited to any specificcellular multi-band and/or multi-system terminal.

Thus, portable terminals 100 may request to execute its idle or activeoperation state cellular transmissions and receptions at frequenciesoutside 860-960 MHz or at least in a frequency band which is spaced atan adequate distance at least in case the UHF radio frequencyidentification (RFID) communication is actively operated. In case thecellular communication subsystem 180 operates at the 850 MHz or 900 MHzfrequency band, it is determined whether a radio frequency band handoveris accomplishable in operation S130. The handover may be an intra-systemhandover and/or an inter-system. The handover operations should berequestable by the portable terminal 100 and the cellular communicationsubsystem 180, respectively.

The intra-system handover should be understood as a handover to anotherfrequency band while preserving currently operated cellular systemstandard, e.g. from GSM 850 (USA) or GSM 900 (Europe) to GSM 1800(Europe) and GSM 1900 (USA), respectively.

The inter-system handover should be understood as a handover to anothercellular system standard which typically includes a frequency bandhandover, e.g. from GSM 900 (Europe) to WCDMA 2100 (Europe) or from GSM850 (USA) to cdma2000 (USA). The inter-system handover may be alsodesignated protocol handover.

It should be noted that requirements and necessitates for performing ofintra-system as well as inter-system handover procedures have to beconsidered. For example, availability of radio frequency resources,availability of PLMNs supporting the desired cellular system standard,provider given limitations and use regulations, etc have to be takeninto account. Details about the requirements could be derived fromhandover procedures defined in the respective cellular standards.

It should be further noted that a protocol handover from GSM to CDMAbased system initiated on request of the terminal 100 (and the cellularcommunication subsystem 180, respectively) may require the adaptation ofthe current standards to enable such a protocol handover. In particular,GSM system does not specify a request allowing a cellular terminal torequest idle or active operation state frequency band handover. Theinvention introduces such a handover procedure including request andresponse framework upon initiation of the portable terminal 100 capablefor cellular communication. The inclusion of such a protocol handoveraccording to an embodiment of the present invention is herewithproposed.

In case the handover is successfully accomplished, the operationalsequence branches to operation S220. Note that the aforementionedcomments on the allowing concurrent operation apply as well.

In operation S140, the radio frequency output power of the radiofrequency identification (RFID) subsystem 190 is lowered. The reductionof the RF output power may accomplish a decreased interference level. Inoperation S150, the interference level in consequence to the reduced RFoutput power of the radio frequency identification (RFID) subsystem isdetermined. In case the interference level is below a pre-definedthreshold, the concurrent operation can be allowed in operation S220.Note that the aforementioned comments on the allowing concurrentoperation apply as well. The defined threshold may depend on priorityconsiderations (prioritization of the cellular communication subsystem180 or the radio frequency identification (RFID) reader subsystem 190),quality of service considerations (bandwidth requirements, interruptionfreeness), and types of communication (e.g. data packets, voice, or datastream communication) currently operated via the cellular communicationsubsystem 180, and the like.

Otherwise, it is checked in operation S160 whether time-alignedoperation of the cellular communication subsystem 180 or the radiofrequency identification (RFID) reader subsystem 190 is allowable. Inparticular, based on the operating profile of the cellular communicationsubsystem (e.g. GSM, cdma2000, and WCDMA, respectively) and the RFoperation related values of radio frequency identification (RFID)subsystem, it is derived whether be time-aligned radio frequencyidentification (RFID) operation in coordination with the cellularcommunication operation (either in idle/standby operation state or inactive operation state) is allowable.

The allowability of time-alignment depends on several conditionsincluding especially whether the cellular communication subsystem 180operates in idle/standby operation state or active operation state andmore particularly, in case of active operation mode whethercommunication mode allows time-alignment. Those skilled in the art willappreciate that the decision whether time-aligned operation is possibleor not requires a closer consideration of the different cellularstandards introduced above. Details thereabout will be illustrated inthe following operational sequence described below with reference toFIG. 4 b.

In operation S170, according to the result of the checking operationS160 the time-aligned operation may be refused or allowed. Upon refuse,the operational sequence branches to operation S210, where for instancethe user is informed that the concurrent and time-aligned operation isnot available, respectively. Otherwise, the operational sequence iscontinued with operation S180, where the operation mode of the cellularcommunication subsystem is determined and depending on the operationmode, the operational sequence branches either to operation S190 oroperation S200 to enable time-aligned operation in idle operation modeas well as in active operation mode of the cellular communicationsubsystem. Details about the idle operation state loop operation (S190)and active operation state loop operation (S200) are worked out in moredetail with reference to FIGS. 4 c and 4 d, respectively.

In operation S230, which follows the idle operation state loop operation(S190) and active operation state loop operation (S200), a selectiverepetition of the check for time-aligned operation may be performed. Incase such a repetition is desired, the operational sequence returns tooperation S160. A selective repetition may be advantageous in view of achanging operation mode and/or communication mode of the cellularcommunication subsystem. More details will be apparent when reading thefollowing description.

With reference to FIG. 4 b, the checking for time-aligned operationaccording to an embodiment of the present invention is carried out inmore detail. Additionally, reference will be given to details concerningdifferent cellular standards.

In operation S240, the operation mode of the cellular communicationsubsystem is obtained. The operation mode may be idle/standby operationstate or active operation state. In operation S245, the operationalsequence branches in dependence on the determined operation mode of thecellular communication subsystem.

In case the operation mode is idle operation state, the time-alignedoperation is allowable according to operation S295. The checkingoperation is finished.

An excursus should be given in the following paragraphs to operations ofthe cellular communication subsystem during idle/standby operation mode.Reference will be given to the aforementioned cellular standards.

GSM, GSM/GPRS, GSM/EDGE:

In case of GSM, GSM/GPRS, GSM/EDGE, the cellular system uses timedivision multiple access (TDMA) (in addition to Frequency DivisionMultiple Access; FDMA) to separate the data and/or voice communicationbetween different cellular terminals within a cell and/or betweenneighboring cells. Hence, basically all communication operations arecarried out in slotted manner with strict timings, i.e. the well-definedstart and end timing of the data communication burst. Therefore, timeframes with time slots are defined. The time slots are selectivelyallocated to one or more cellular terminals and channels. Inconsequence, each cellular terminal has its own determined intervals,within which transmission and/or reception is operable.

In general, the cellular communication subsystem does not operate anydata or voice communication during idle operation state except of pagingand measurement related communication.

In idle operation mode, a GSM/EDGE enabled terminal for instance listensto the Common Control Channel (CCCH) in order to discover possiblepaging done by the radio access network (RAN), base station (BS), thenode B, or the like. The CCCH listening also ensures frequency and timesynchronization of the cellular communication subsystem. The CCCH isreceived and decoded according to a pre-defined DRX (discontinuousreception) period, i.e. from once per two to once per nine 51multi-frames (listening interval of approximately 0.5 s-2 s). Typically,the listening interval on the CCCH is about 2 seconds. In addition, aminimum of seven neighboring cells are monitored every time a page islistened to. The terminal does not transmit anything in the idleoperation mode unless there is a need to do so. A need could be a callinitiation in accordance with a user originated call, a response to acall set-up request (indicated by the means of a paging message) inaccordance with mobile station terminated call, a periodic locationupdate, etc. In case there are not any services in use, location updatesare in practice the only activities requiring transmissions carried outby the cellular communication subsystem of the portable terminal. Hence,in general, during the idle operation mode, a GSM/EDGE enabled terminallistens to the CCCH for two to four slots in two seconds, and performsthe received signal level measurements for the neighboring cell of thepublic land mobile network (PLMN); i.e. the base station (BS) of theneighboring cell. All other operations occur quite seldom, and thereforethe CCCH reception mostly determines the allowed radio frequencyidentification (RFID) activity in this case.

Analog considerations apply to GSM and GSM/GPRS in idle operation mode.As a result, there are available periods of non-activity of the cellularcommunication subsystem during which (UHF) radio frequencyidentification (RFID) communication can be carried out. Moreover, theperiods of activity of the GSM, GSM/GPRS, or GSM/EDGE cellularcommunication subsystem in idle operation mode and consequently also theperiods of non-activity are well-defined.

WCDMA and CDMA (cdma2000):

Both cdma2000 and WCDMA (Wideband Code Division Multiple Access such asUMTS) utilize CDMA (Code Division Multiple Access) methodology as amultiple access method. The basis of CDMA is formed by spread spectrummodulated signals. A spread spectrum modulated signal is typicallycontinuous by nature, and therefore the scheduling solution differs fromthe aforementioned GSM, GSM/GPRS, or GSM/EDGE case.

During the idle operation mode, a cdma2000 enabled terminal listens tothe Forward Pilot Channel (F-PCH) of its own and neighboring cells inorder to detect messages directed to it and measure the pilot strengthto determine the need of an idle handoff. In addition, the cdma2000enabled terminal listens to the Paging Channel (PCH) to detect possibleincoming calls. It takes an average about 100 ms to listen to its ownslot during the F-PCH slot cycle length of 2^(SCI) (SCI:SLOT_CYCLE_INDEX) in units of 1.28 s (e.g. SCI=1 (2^(SCI)=2) in US andSCI=2 (2^(SCI)=4) in Japan, typically). In case the cdma2000 PLMNsupports Forward Quick Paging Channel (F-QPCH) indicators, the cdma2000enabled terminal listens to its F-QPCH indicator for about 20 ms inaddition to the listening of the slotted page, which happensapproximately once in a minute.

In IS-2000 Release A the idle operation mode is a bit different from theone described above. The F-BCCH (Forward Broadcast Control Channel)containing overhead messages is only decoded when there is a need toaccess or when a new pilot is detected indicating a possible idlehandoff. The F-CCCH (Forward Common Control Channel), carrying pagemessages to cellular terminals, is decoded when a page is detected onF-QPCH.

In case of WCDMA idle operation mode the WCDMA enabled terminal iscamped to a cell, listens to system information, paging and notificationmessages and performs regular measurements to find out the strongestbase station (BS) signal and neighboring base stations (BS, nodeB, etc)as well. Signal levels of the serving cell are measured at least everyDRX (discontinuous reception) cycle (from 0.64 s to 5.12 s in idleoperation state). There are also intra-frequency cell measurements (witha measurement cycle of 1.28 s to 5.12 s in idle operation state) andinter-frequency cell measurements (each frequency in every(N_(carrier)−1)*1.28 s to (N_(carrier)−1)*5.12 s cycle). Pagingcomprises listening to BCH and PCH transport channels sent in P-CCPCH(Primary Common Control Physical Channel) and S-CCPCH (Secondary CommonControl Physical Channel), respectively. The WCDMA enabled terminal mayalso use discontinuous reception (DRX) in idle operation state, and inthat case the WCDMA enabled terminal only needs to monitor one pagingindicator from the Paging Indicator Channel (PICH). This happens once ineach DRX cycle. Naturally, if the terminal initiates a call (terminaloriginated call), a message is sent on the RACH (Random Access Channel).

As a result, there are available periods of non-activity of the cellularcommunication subsystem, during which (UHF) radio frequencyidentification (RFID) communication can be carried out. Moreover, theperiods of activity of the CDMA or WCDMA cellular communicationsubsystem in idle operation mode and consequently also the periods ofnon-activity are well-defined.

Referring back to FIG. 4 b, in case the operation mode is activeoperation state an allowability of time-aligned operation or a refusingof time-aligned operation requires a more detailed consideration of thedifferent cellular system standards.

In operation S250, it is checked whether the cellular communicationsubsystem is operable with GSM, GSM/GPRS, or GSM/EDGE communication and,in case the check matches, it is determined whether the time slotallocation enables time-aligned operation.

As aforementioned, a GSM, GSM/GPRS, or GSM/EDGE enabled cellular systemuses time division multiple access (TDMA) (in addition to frequencydivision multiple access (FDMA)) to separate the data and/or voicecommunication between different cellular terminals within a cell and/orbetween neighboring cells. Hence, basically all communication operationsare carried out in slotted manner with strict timings, i.e. well-definedthe start and end timing of the data communication burst. This means,the decision of allowability or refuse of time-aligned operation has toconsider whether time slots are available at which the cellular systemis inactive (i.e. inactive in the means that one or more time-slots of aframe are not allocated to transmission or reception of data).

During either voice call or GPRS data call the cellular communicationsubsystem is active during its uplink and downlink slots of the TDMA(Time Division Multiple Access) frame, which are allocated for datauplink as well as data downlink transmission. There might be more thanone slot allocated to the cellular communication subsystem in both(uplink and downlink) directions. Additionally, the cellularcommunication subsystem monitors the neighboring base stations (BS,nodeB, etc) once in a TDMA frame (comprising eight time slots), one basestation at a time. According to the concept of the present invention,the radio frequency identification (RFID) reader subsystem collocatedwith a GSM, GSM/GPRS, or GSM/EDGE cellular communication subsystem hasto avoid carrier wave transmission during the active periods of thecellular communication subsystem as aforementioned.

According to an embodiment of the present invention, FIG. 5 aillustrates representatively an activity diagram of GSM/EDGE subsystemoperated in time-aligned way with a radio frequency identification(RFID) reader subsystem. In particular, the activity diagrams illustrateactivity states in case of a GSM/EDGE Dual Transfer Mode (DTM) caseshowing illustratively the interweaving of the activity periods of theboth subsystems. FIG. 5 a illustrates an allocation of two time slots(RX time slots #1 and #2) for downlink communication (RX) and one timeslot (TX time slot #2) for uplink communication (TX). In addition, oncein a TDMA frame (comprising times slots #0 to #7) one of the neighboringbase stations (BS, nodeB, etc) is monitored on the basis of ameasurement operation. The measurement operation is exemplarilyinterposed between time slots #4 and #5 with respect to the TDMAstructure of the uplink communication channel. It should be noted thatthe uplink and downlink time slot allocation is exemplary; other timeslot allocations for uplink communication and/or downlink communicationmay be used. In accordance with the uplink and downlink communication aswell as the measurement operation, two periods of non-activity per eachTDMA frame can be identified; i.e. a first period of non-activity(comprising substantially the TX time slots #0 and #1) interposedbetween the downlink operation and the uplink operation and a secondperiod of non-activity (comprising substantially the TX time slot #3 anda part of TX time slot #4) interposed between the uplink operation andthe measurement operation. These periods of non-activity of the cellularcommunication subsystem are applicable for operating the radio frequencyidentification (RFID) reader subsystem as exemplarily illustrated inFIG. 5 a with respect to the RFID reader operation CW (continuous wave)window.

The skilled reader understands on the basis of the illustration of FIG.5 a that depending on the time slot allocation in TDMA systems one ormore periods of non-activity may be available within the slotted timestructure. These periods of non-activity of the cellular communicationsubsystem are applicable for operating the radio frequencyidentification (RFID) subsystem without having to be afraid of sufferingof interference generated by cellular communication subsystem and theradio frequency identification (RFID) subsystem.

It should be also noted that the allocation of time slots for uplink anddownlink communication is requestable by the cellular communicationsubsystem of the terminal. As a result, an adequate time slot allocationmay be requested to obtain periods of non-activity which enablestime-aligned operation of the both subsystems. The requesting of anadequate time slot allocation may be accompanied by a reduced uplinkand/or downlink data rate of the cellular communication subsystem butenables advantageously the time-aligned operation.

As a result, depending on the time slot allocation time-alignedoperation of the both subsystems may be allowed or rejected. In thefirst case of allowance, the operational sequence continues withoperation S295, whereas in the latter case of rejection, the operationalsequence continues with operation S290. In operation S290, thetime-aligned operation is refused.

In operation S260, it is checked whether the cellular communicationsubsystem is operable with WCDMA communication and, in case the checkmatches, it is determined whether the communication mode is applicablewith time-aligned operation, in operation S265.

As aforementioned, WCDMA (Wideband Code Division Multiple Access such asUMTS) utilizes CDMA (Code Division Multiple Access) methodology as amultiple access method. The basis of CDMA is formed by spread spectrummodulated signals. A spread spectrum modulated signal is typicallycontinuous by nature, and therefore the scheduling solution differs fromthe aforementioned GSM, GSM/GPRS, or GSM/EDGE case.

While having a voice or data call in the WCDMA active operation mode,the cellular communication subsystem may use compressed mode to enableseemingly concurrent radio frequency identification (RFID) readeroperation. Reference should be given to FIG. 5 b, which illustrates anexemplary time structure of a compressed mode communication. AlthoughWCDMA utilizes CDMA (Code Division Multiple Access) methodology as amultiple access method time multiplexing is likewise applied to separatedifferent channels in the physical layer. The time multiplexingstructure is typically based on a time frame structure, where each timeframe comprises 15 time slots.

In the compressed (or slotted) mode the base station (BS, nodeB, etc),to which the cellular communication subsystem is communicates, assignstransmission gaps both in downlink and uplink to enable inter-cellmeasurements performed by the cellular communication subsystem of theterminal. Such inter-cell measurements are required for inter-frequencyhandover of the cellular communication subsystem of the terminal and areperformed on the different WCDMA carrier frequencies. Several time slotscan be allocated to perform this measurement. These allocated slots canbe either in the middle of a single frame of spread over two frames.

In order to enable radio frequency identification (RFID) readeroperation one, some or, all of the measurements supposed to be performedby the terminal (and the subsystem thereof, respectively) are skipped toleave sufficient time of non-activity applicable for operation of theradio frequency identification (RFID) subsystem. The Transmission GapLength (TGL) and their timing are determined by the cellular RadioAccess Network (RAN). The compressed frames are simultaneous in time inboth uplink and downlink. The specified Transmission Gap Lengths (TGLs)are 3, 4, 7, 10, and 14 slots, i.e. from 2 ms to 9.3 ms.

The compressed mode operation can be achieved in different methodsincluding decreasing of the spreading factor (e.g. by 2:1), puncturingbits (i.e. resulting to a reduced amount of information to betransmitted), or changed scheduling at higher layers (e.g. to requireless time slots for communication).

With reference to FIG. 5 b (1), in a compressed frame the slots from#N_(first) to #N_(last) defining the Transmission Gap Length are notused for data transmission. As illustrated exemplarily, theinstantaneous transmit power is increased in the compressed frame inorder to keep the quality of Service (Bit Error Rate, Frame Error Rate,etc.) unaffected by the reduced processing gain. The amount of powerincrease depends on the transmission time reduction method illustratedabove. The frames to be compressed are indicated by the network.Principally in compressed mode, compressed frames can occurperiodically, or requested on demand. The rate and type of compressedframes is variable and depends on the environment and the measurementrequirements.

With reference to FIGS. 5 b (2)-(4), different frame structures foruplink and downlink compressed frames are illustrated. Referringparticularly to the downlink compressed frame structure, there are twodifferent types of frame structures defined. Type A (cf. FIG. 5 b (3))maximizes the Transmission Gap Length (TGL), whereas type B is optimizedfor power control. The frame structure type A or B is set by higherlayers independent from the downlink slot format type A or B. With framestructure of type A, the pilot field of the last slot in thetransmission gap is transmitted. Transmission is turned off during therest of the transmission gap. With frame structure of type B, the TPCfield of the first slot in the transmission gap and the pilot field ofthe last slot in the transmission gap are transmitted. Transmission isturned off during the rest of the transmission gap.

Although, the compressed mode communication, Transmission Gap Length(TGL) and its timing are determined by the cellular Radio Access Network(RAN) those skilled in the art will appreciate that provisions may bemade to enable the cellular communication subsystem of the terminal toinstruct compressed mode communication and to determine its properties(length, timing).

As a result, compressed mode communication may be requested by theterminal to obtain periods of non-activity which enables time-alignedoperation of the both subsystems. The originally arranged measurementoperations are omitted. The requesting of compressed mode communicationmay be accompanied by a reduced uplink and/or downlink data rate of thecellular communication subsystem but enables advantageously thetime-aligned operation.

As a result, depending on the communication mode time-aligned operationof the both subsystems may be allowed or rejected. In the first case ofallowance, the operational sequence continues with operation S295,whereas in the latter case of rejection, the operational sequencecontinues with operation S290. In operation S290, the time-alignedoperation is refused.

In operation S270, it is checked whether the cellular communicationsubsystem is operable with cdma2000 communication and, in case the checkmatches, it is determined whether the communication mode is applicablewith time-aligned operation, in operation S275.

As aforementioned, cdma2000 utilizes also CDMA (Code Division MultipleAccess) methodology as a multiple access method. The basis of CDMA isformed by spread spectrum modulated signals. A spread spectrum modulatedsignal is typically continuous by nature, and therefore the schedulingsolution differs from the aforementioned GSM, GSM/GPRS, or GSM/EDGEcase.

The cdma2000 enabled terminal activity is generally continuous while inactive operation state. The only exception is Discontinuous Transmission(DTX) mode. In Discontinuous Transmission (DTX) mode, the activity ofthe cellular communication subsystem of the terminal is only 50% of thenominal on the reverse link (i.e. uplink direction). Similarly, there isalso discontinuous transmission available for the forward link (i.e.downlink direction). These gaps in transmission and reception in uplinkand downlink could be used to enable radio frequency identification(RFID) operation.

However it should be noted that Discontinuous Transmission (DTX) mode isonly allowed in F-DCCH (Forward Dedicated Control Channel in cdma2000)and R-DCCH (Reverse Dedicated Control Channel), but voice data cannot betransferred on those channels.

If necessary, Discontinuous Transmission (DTX) mode may be requested bythe cdma2000 enabled terminal. The requesting of DiscontinuousTransmission (DTX) mode communication may be accompanied by a reduceduplink and/or downlink data rate of the cellular communication subsystembut enables advantageously the time-aligned operation.

As a result, depending whether Discontinuous Transmission (DTX) mode isavailable and applicable, time-aligned operation of the both subsystemsmay be allowed or rejected. In case of allowance, the operationalsequence continues with operation S295, whereas in case of rejection,the operational sequence continues with operation S290. In operationS290, the time-aligned operation is refused.

Those skilled in the art will appreciate that the concept of the presentinvention described on the basis of the aforementioned embodied TDMAbased cellular communication subsystems and CDMA based cellularcommunication subsystems is also applicable with other TDMA and CDMAbased communication subsystems, respectively. This means that schedulingof a radio frequency identification (RFID) reader subsystem according toan embodiment of the present invention should not be limited to theaforementioned cellular communication subsystems.

In general, periods of non-activity are often provided in wirelesscommunication systems to enable reduction of the power consumption ofthe respective wireless communication subsystem. The consideration ofthe power consumption addresses especially portable terminals (such asterminal 100), which are supplied by batteries and/or accumulatorsproviding only a limited overall energy capacity. During periods ofnon-activity, the wireless communication subsystem may be power-down orat least operated in power saving modes.

In view of the aforementioned discussion of the necessities andconstraints required to enable time-aligned operation of the cellularcommunication subsystem and radio frequency identification (RFID) readersubsystem, reference should now be given to FIG. 4 c which showsschematically an operational sequence of the idle/standby operationstate loop procedure according to an embodiment of the presentinvention. The idle/standby operation state loop procedure is part ofthe overall operational sequence described above with reference to FIG.4 a.

Typically during the idle/standby operation mode the cellularcommunication subsystem of the terminal listens to the paging messagescoming from the PLMN and base station (BS, nodeB, etc), respectively, inorder to know whether a communication connection is to be established.Hence, when the radio frequency identification (RFID) enabled cellularterminal is switched on or the radio frequency identification (RFID)reader functionality of a cellular terminal is enabled, the schedulingof the time-aligned operation starts to operate according the followingmonitoring loop operations according to an embodiment of the presentinvention.

In operation S300, when attaching of the cellular communicationsubsystem to the Radio Access Network (RAN) or the base station (BS,nodeB, etc), or later on regularly during the idle/standby state, thecellular communication subsystem receives one or more system informationmessages, which include information about the paging group, to which thecellular communication subsystem is assigned, and hence also the pagingtiming.

In operation S310, when attaching of the cellular communicationsubsystem to the Radio Access Network (RAN) or the base station (BS,nodeB, etc), or later on regularly during the idle/standby state, thecellular communication subsystem receives also system informationmessages timing information about potential signal level measurements ofneighboring base stations.

In operation S320, upon obtainment of the information relating to paginginstances as well as information relating to the measurement instances,the information is supplied to the scheduler. Based on the timinginformation about the paging instants and measurement instants, thescheduler is synchronized to the paging and measurement timing in such away that exact paging and measurement instants and their lengths areknown. As a result, the scheduler is informed about the exact timing ofthe periods of activity and non-activity of the cellular communicationsubsystem; in particular, start and end timing of the activity andnon-activity periods of the cellular communication subsystem.

In operation S330, further configuration of the scheduler and/or theradio frequency identification (RFID) reader subsystem is operable.Reference should be given to the description below.

In operation S340, the operation of the radio frequency identification(RFID) reader subsystem may be initiated. The initiation may be causedupon reception of a user input to the terminal or upon an initiationsignal generated by an application executable on the terminal. Uponindication to initiate, the operational sequence continues withoperation S350, otherwise the operational sequence branches to operationS360.

In operation S350, the scheduler aligns the radio frequencyidentification (RFID) reader operation timing in such a way that theoperation is performed during periods of non-activity of the cellularcommunication subsystem. The periods of non-activity are determined onthe basis of the information relating to paging instances as well asinformation relating to the measurement instances (cf. operation S320).

In an operation S360, it is checked whether new information concerningthe scheduling of the time-aligned operation (i.e. paging instancesrelated information and/or measurement instances related information) isavailable e.g. from system messages received from the Radio AccessNetwork (RAN) by the cellular communication subsystem of the terminal.In case new information is available, the operational sequence returnsto operation S300, otherwise the operational sequence continues withoperation S370.

In operation S370, the time-aligned operation of the radio frequencyidentification (RFID) subsystem may be repeatedly performed. Theoperational sequence may return to operation S340 or to operation S350,when for example the radio frequency identification (RFID) subsystemoperation is divided into several single radio frequency identification(RFID) subsystem operations.

It should be noted that operation mode of the cellular communicationsubsystem may change. This means, upon indication of the Radio AccessNetwork (e.g. paging message, mobile terminated call set-up message,etc.) or in response to a user request (e.g. mobile originated callset-up message) the cellular communication subsystem may change fromidle/standby operation mode to active operation mode. In case of achange of the operation mode to active operation mode the operationalsequence may return to S160 described with respect to FIG. 4 a, in orderto check allowability of time-aligned operation in active operationmode.

In view of the aforementioned discussion of the necessities andconstraints required to enable time-aligned operation of the cellularcommunication subsystem and radio frequency identification (RFID) readersubsystem, reference should also be given to FIG. 4 d, which showsschematically an operational sequence of the active operation state loopprocedure according to an embodiment of the present invention. Theactive operation state loop procedure is part of the overall operationalsequence described above with reference to FIG. 4 a.

In case of active operation state (i.e. either voice call or data callcurrently performed) or states requiring similar kind of activity as theactual active operation state (e.g. ready state in GSM/GPRS), the radiofrequency identification (RFID) subsystem operation has to be scheduledin such a way that overlap with cellular communication subsystemactivity is prevented. According to an embodiment of the presentinvention, the active operation state includes the following operations.

In operations S400 and S410, the communication standard and mode as wellas the activity timing related information is obtained. In particular,when the terminal enters the active (or similar) operation state, orlater on regularly during the active operation state, the communicationstandard and mode (GSM, GSM/GPRS, GSM/EDGE, WCDMA compressed mode,cdma2000 DTX mode, etc.) and activity timing related information of thecellular communication subsystem is determined. The activity timingrelated information include especially the active slot timing in case ofGSM, GSM/GPRS, GSM/EDGE, TGL timing in WCDMA compressed mode, orDiscontinuous Transmission (DTX) timing in cdma2000 is obtained from thecellular communication subsystem. Reference should be given to thediscussion given above with reference to FIG. 4 b.

In operation S420, upon obtainment of the timing related information,the information is supplied to the scheduler. Based on the timinginformation about the paging instants and measurement instants, thescheduler is synchronized on the basis of the timing related informationin such a way those non-activity periods and their lengths are known. Asa result, the scheduler is informed about the exact timing of periods ofactivity and non-activity of the cellular communication subsystem; inparticular, start and end timing of the activity and non-activityperiods of the cellular communication subsystem.

In operation S430, further configuration of the scheduler and/or theradio frequency identification (RFID) reader subsystem is operable.Reference should be given to the description below.

In operation S440, the operation of the radio frequency identification(RFID) reader subsystem may be initiated. The initiation may be causedupon reception of a user input to the terminal or upon an initiationsignal generated by an application executable on the terminal. Uponindication to initiate, the operational sequence continues withoperation S450, otherwise the operational sequence branches to operationS460.

In operation S450, the scheduler aligns the radio frequencyidentification (RFID) reader operation timing in such a way that theoperation is preformed during periods of non-activity of the cellularcommunication subsystem. The periods of non-activity are determined onthe basis of the timing related information (cf. operation S420).

In an operation S460, it is checked whether new information concerningthe scheduling of the time-aligned operation (i.e. paging instancesrelated information and/or measurement instances related information) isavailable e.g. from system messages received from the Radio AccessNetwork (RAN) by the cellular communication subsystem of the terminal.In case new information is available, the operational sequence returnsto operation S300, otherwise the operational sequence may continue withoperation S470.

In operation S470, the time-aligned operation of the radio frequencyidentification (RFID) subsystem may be repeatedly performed. Theoperational sequence may return to operation S440 or to operation S450,when for example the radio frequency identification (RFID) subsystemoperation is divided into several single radio frequency identification(RFID) subsystem operations.

It should be noted that operation mode of the cellular communicationsubsystem may change. This means, upon indication of the Radio AccessNetwork or in response to a user request the cellular communicationsubsystem may change from active operation mode to idle/standbyoperation mode. In case of a change of the operation mode toidle/standby operation mode the operational sequence may return to S160described with respect to FIG. 4 a, in order to check allowability oftime-aligned operation in idle/standby operation mode or may directlybranch to operation S300 described with respect to FIG. 4 c.

The aforementioned description of the scheduling algorithm is focused onthe requirements, which have to be met to enable principletime-alignment of the both subsystems. In the following, an optimizedoperation of the radio frequency identification (RFID) reader subsystemwill be described. The optimization is advantageous to enable aneffective operation of the radio frequency identification (RFID) readersubsystem within the non-activity periods, during which operativeness isallowable. According to an embodiment of the present invention, aconfiguration and control interface, preferably an application programinterface (API), is provided to control and configure the operation ofthe radio frequency identification (RFID) reader subsystem. Theconfiguration and control interface to the radio frequencyidentification (RFID) reader subsystem may be realized by data andcommand exchange through the data interface of the radio frequencyidentification (RFID) reader subsystem. It should be noted that theaforementioned specific digital I/O trigger signal terminal utilizableto synchronize the operation of the radio frequency identification(RFID) reader subsystem may be implemented as a separate signal inputterminal to the watchdog logic of the radio frequency identification(RFID) reader subsystem or alternatively, the trigger signal may besupplied to the watchdog logic of the radio frequency identification(RFID) reader subsystem through the data interface thereof, as well. Aseparate trigger signal terminal may be preferable in order to ensuresynchronicity with the trigger signal.

The configurability of the radio frequency identification (RFID) readersubsystem is preferably under the control of the scheduler, which alsotriggers the operation of the radio frequency identification (RFID)reader subsystem. Back reference should be given to the operations S330and S430 of the idle and active operation mode loop procedures,respectively.

In general, the scheduling mechanism described in detail above usestiming related information to identify activity and non-activity periodsof the cellular communication subsystem such that the scheduler preventsfrom operating the radio frequency identification (RFID) readersubsystem while the cellular communication subsystem operates, i.e.while the cellular communication subsystem for instance receives pagingmessages, performs measurements, sends or receives data packets, orsends random access data bursts. Among others, the scheduler is arrangedto configure the maximum duration of a single RF emission to be notgreater than a period of non-activity of the cellular communicationsubsystem and triggers the operation of the radio frequencyidentification (RFID) reader subsystem in correspondence with theexpected start of the period of non-activity. The scheduler may use thespecified digital I/O trigger signal terminal to trigger synchronized RFactivity of the radio frequency identification (RFID) reader subsystem.

Reference should be given to FIG. 6 a, which illustrates exemplary anactivity time sequence on the basis of the GSM/EDGE DTM activity diagramshown in FIG. 5 a according to an embodiment of the invention. For theway of illustration, a first period of activity Δ_(aI) and a secondperiod of activity Δ_(aII) is identified as well as a first period ofnon-activity Δ_(nI) and a second period of non-activity Δ_(nII) isidentified. In accordance with the periods of non-activity, RF signalperiods of the radio frequency identification (RFID) reader subsystemare indicated as RFID Reader RF Activity Windows (cf. legend of FIG. 6a) signifying an RF emission, in conformance with the signal powerlevel, accuracy and integrity requirements, from the antenna of theradio frequency identification (RFID) reader subsystem.

An optimized time for setting the trigger signal to start RF activity ofthe radio frequency identification (RFID) reader subsystem is a durationΔ_(I), which represents a ramp-up duration Δ_(I). The ramp-up durationΔ_(I) is required by the radio frequency identification (RFID) readersubsystem from receiving the trigger signal to beginning to transmit anRF signal in conformance with the signal power level, accuracy andintegrity requirements of the radio frequency identification (RFID)reader system, from the antenna of the radio frequency identification(RFID) reader subsystem. Inter alia, the ramp-up duration Δ_(I) iscaused by PLL (Phased Loop Lock) settling, micro-controller/logicwarm-up, settling time of the RF interface, and/or other necessitiesbefore RF activity.

Preferably, an additional guard duration Δ_(II) should be consideredbetween the end of the period of activity of the cellular communicationsubsystem and the beginning of the RF signal emission of the radiofrequency identification (RFID) reader subsystem.

When considering the ramp-up duration Δ_(I) and the guard durationΔ_(II), the trigger signal initiating the operation of the radiofrequency identification (RFID) reader subsystem should be setΔ_(I)−Δ_(II) before an end of a period of activity of the cellularcommunication subsystem. When defining arbitrarily a reference point intime 0 coincident with an end of a period of activity as well as thebeginning of a period of non-activity of the cellular communicationsubsystem, the trigger signal should be set at a point in timeT_(I)=Δ_(II)−Δ_(I)<0. The emission of a RF signal from the radiofrequency identification (RFID) reader subsystem begins correspondinglyat a point in time T_(II)=Δ_(II)>0, which is equal to the guard durationΔ_(II).

An optimized time for the resetting (releasing) the trigger signal tostop RF activity of the radio frequency identification (RFID) readersubsystem is a duration Δ_(III), which represents a ramp-down durationΔ_(III). The ramp-down duration Δ_(III) is required by the radiofrequency identification (RFID) reader subsystem from detecting thetrigger signal reset to the termination of the RF signal emissiongenerated by the radio frequency identification (RFID) reader subsystem.The RF emission will be terminated before the start of the activity ofthe cellular communication subsystem, and hence also before time instant0′ and the end of the period Δ_(III). In contrast to the ramp-upduration Δ_(I), there is no need to ensure sufficient settling times ofthe PLL (phase-locked loop), the RF interface etc. during Δ_(III) intermination of the RF activity, since the power level, accuracy andintegrity of the RF signal is not relevant as long as the output stageis disabled and there isn't any RF emission from the antenna of theradio frequency identification (RFID) reader subsystem.

When considering the ramp-down duration Δ_(III), the trigger signalreset terminating the operation of the radio frequency identification(RFID) reader subsystem should be set Δ_(III) before an end of a periodof non-activity of the cellular communication subsystem. When definingarbitrarily a reference point in time 0′ coincident with an end of aperiod of non-activity as well as the beginning of a period of activityof the cellular communication subsystem, the trigger signal should beset at a point in time T_(III)=−Δ_(III)<0′. Thus, the emission of an RFsignal terminates correspondingly during a time period finishing beforea reference point in time 0′, such that interference with cellularactivity is avoided.

Those skilled in the art will appreciate that the period of operation ofthe radio frequency identification (RFID) reader subsystem may beoptimized by adjusting the guard duration Δ_(II) and considering theramp-up duration Δ_(I) as well as the ramp-down duration Δ_(I). Theramp-up duration Δ_(I) as well as the ramp-down duration Δ_(III) aretypically specific for the employed radio frequency identification(RFID) reader subsystem.

Further parameters of the radio frequency identification (RFID) readersubsystem may also enable adjustment and/or optimization of theoperation of the radio frequency identification (RFID) reader subsystem.An optimization and adjustment of the operation of the radio frequencyidentification (RFID) reader subsystem is advantageous to utilizeeffectively the periods of non-activity of the cellular communicationsubsystem and adjust the operation of the radio frequency identification(RFID) reader subsystem to the specific lengths of periods ofnon-activity. The adjustment and/or optimization may includemodification of some of the parameters of the radio frequencyidentification (RFID) reader subsystem.

Static Information:

The scheduler should be informed about at least a sleep clock cycle ofthe radio frequency identification (RFID) reader subsystem and therequired ramp-up and ramp-down duration before RF activity and after RFactivity of the radio frequency identification (RFID) reader subsystem.Also information relating to minimum, default, and maximum values aswell as units of further parameters, which are enlisted below, should beavailable at the scheduler. This information is typically disclosed bymanufacturer of the employed radio frequency identification (RFID)reader subsystem at a data sheet. The information is preferably storedin the scheduler or stored in the terminal to be accessible by thescheduler when required.

Semi-Static Standard Related Information:

Inter alia, the scheduler may obtain and optionally modify the followingparameter values that are relevant to the duration of RF activity.Reference should be given to the EPCglobal standard generation 2.Following parameters may be relevant and will be described withreference to FIGS. 6 b to 6 d.

With reference to FIG. 6 b, the power-up as well as power-down RFenvelope of the interrogation RF signal is depicted. Reference should begiven to the aforementioned discussion of the ramp-up duration andramp-down duration. The rise time T_(r) and fall time T_(f) illustratedin FIG. 6 b is comprised by the ramp-up duration Δ_(I). and ramp-downduration Δ_(III). However, it should be noted that FIG. 6 b illustratesmerely the envelope of the RF signal detectable at the RF interface ofthe radio frequency identification (RFID) reader subsystem. The risetime T_(r) and fall time T_(f) should be within the time range from 1 μsto 500 μs. After power-up, the interrogation signal requires a settlingtime T_(s) before being substantially at a constant level (100% powerlevel). The settling time T_(s) should be within the time range from 0to 1500 μs. During power-up, the envelope should rise monotonically whenexceeding the 10% power level until at least the ripple limit M_(l) (95%power level). During power-down, the envelope should decreasemonotonically when falling below between 90% power level until at leastthe power of limit M_(s) (1% power level). The power levels M_(l)(undershoot, max. 95%) and M_(h) (overshoot, max. 105%) define the powerlevel boundaries of the RF envelope.

It should be noted that in some regions a carrier sensing attempt has tobe performed before beginning radio frequency identification (RFID)communication. For instance with respect to ETSI (EuropeanTelecommunications Standards Institute) regulations, which especiallyhave to be considered in Europe, the use of radio frequencyidentification (RFID) communication for instance at a frequency rangefrom 865 MHz to 868 MHz presupposes a so-called “Listen-Before-Talk”(LBT) operation. The Listen-Before-Talk (LBT) operation is provided todetect whether a distinct frequency sub-band intended for radiofrequency identification (RFID) communication is currently occupied orfree (unoccupied). The detection should avoid collisions of thecommunications at the same radio frequency sub-band. For instanceaccording to ETSI specifications, immediately prior to eachcommunication by a radio frequency identification (RFID) readersubsystem, the radio frequency identification (RFID) reader subsystemhas to be switched into a so-called listen mode in which one or morepre-selected frequency sub-bands are monitored for a specific listeningperiod of time, which will be also designed as carrier sensing periodT_(LSB). The carrier sensing period T_(LSB) (for instance in accordancewith the ETSI regulations) should comprise a fixed time interval e.g. 5ms and a random time interval e.g. in the time range from 0 ms to r ms,in particular in the time range from 0 ms to 5 ms. In case the monitoredsub-band is free (unoccupied), the random time interval is set to 0 ms.The ETSI specifications further define certain permitted minimum levelsfor threshold levels, which define sensitivity characteristics. Thesepermitted minimum levels are dependent on the transmission power levelintended to be used for radio frequency identification (RFID)communication. Note that the variable carrier sensing period T_(LSB)(equal to a variable period of time in the time range from 5 ms to 10ms) should be also considered when adjusting and/or optimizing of theoperation of the radio frequency identification (RFID) reader subsystem.

With reference to FIG. 6 c, the data encoding on physical layer isdepicted. In particular, the RF envelope signal of coding symbols data-0and data-1 used for data encoding is depicted. T_(ari) is the referencetime interval for interrogator-to-tag signaling (i.e. radio frequencyidentification (RFID) reader subsystem to transponder signaling) andrepresents a duration of the data-0 symbol representing for instancebinary 0. The value x (within the value range from 0.5 to 1.0) definesthe data-1 duration on the basis of the reference time interval T_(ari),i.e. value x defines a relative reference time interval forinterrogator-to-tag signaling and represents a duration of the data-1symbol on the basis of the duration of the data-0 symbol, where thedata-1 symbol represents for instance binary 0. High values representtransmitted continuous wave (CW), which is designated aboveinterrogation or excitation RF signal, as well. Low values representattenuated CW. The modulation depth, rise time, fall time and pulsewidth are defined. Valid values of the aforementioned parameters dependon the type of modulation employed for communication to the transponderincluding Double Side-Band Amplitude-Shift Keying (DBS-ASK), SingleSide-Band Amplitude-Shift Keying (SSB-ASK), and Phase-ReversalAmplitude-Shift Keying (PR-ASK), which have to be supported by thetransponders. According to the type of modulation the reference timeinterval T_(ari) can have the values 6.25 μs (for DSB-ASK), 12.5 μs (forSSB-ASK), and 25 μs (for PR-ASK). Moreover, modulation depth should beminimal 80%, typically 90%, and maximal 100%. The RF envelope rise time(10%→90%) and the RF envelope rise time (90%→10%) should be within therange of 0 to 0.33*T_(ari). The RF pulse width should be within therange of MAX(0.265*T_(ari), 2) to 0.525*T_(ari).

The RF pulse width, RF envelope rise time, the RF envelope fall time arespecific for radio frequency identification (RFID) reader subsystem.These parameters can only be read and are not modifiable. The carrierfrequency may be selected from the frequency range from 860 MHz to 960MHz. However, local regulations have to be considered and the carrierfrequency should be determined additionally by local radio frequencyenvironment.

With reference to FIG. 6 d, an exemplary Reader to Transponder (R→T) andTransponder to Reader (T→R) link timing is illustrated. The Reader toTransponder (R→T) communication is based on the continuous wave (CW),which corresponds to the aforementioned RF interrogation/excitationsignal. The continuous wave is continuously emitted by the radiofrequency identification (RFID) reader subsystem to ensure energizing ofthe radio frequency identification (RFID) transponder. For accessing theinformation stored by the radio frequency identification (RFID)transponder, the set of commands are provided, which can be modulatedonto the continuous wave.

In more detail, the radio frequency identification (RFID) readersubsystem is enabled sending information to one or more radio frequencyidentification (RFID) transponders by modulating a RF carrier(continuous wave (CW); interrogation or excitation RF signal) usingdouble-sideband amplitude shift keying (DSB-ASK), single-sidebandamplitude shift keying (SSB-ASK) or phase-reversal amplitude shiftkeying (PR-ASK) using a pulse-interval encoding (PIE) format. The radiofrequency identification (RFID) transponders are arranged to receivetheir operating energy from this same modulated RF carrier.

A radio frequency identification (RFID) reader subsystem is furtherarranged to receive information from a radio frequency identification(RFID) transponder by transmitting an unmodulated RF carrier (continuouswave (CW); interrogation or excitation RF signal) and listening for abackscattered reply. Radio frequency identification (RFID) transponderscommunicate information by backscatter-modulating the amplitude and/orphase of the RF carrier. The encoding format, selected in response toradio frequency identification (RFID) reader subsystem commands, is forexample either FMO or Miller-modulated subcarrier. The communicationslink between a radio frequency identification (RFID) reader subsystemand radio frequency identification (RFID) transponder is half-duplex,meaning that radio frequency identification (RFID) transponder shouldnot be required to demodulate radio frequency identification (RFID)reader subsystem commands while backscattering. A radio frequencyidentification (RFID) transponder should not respond using full-duplexcommunications.

Exemplarily, a select, query and acknowledgement command is depicted.Before issuing a command to the radio frequency identification (RFID)transponder, the radio frequency identification (RFID) reader should atleast emit the continuous wave for eight times of theInterrogator-to-Tag calibration symbol RT_(cal) period, where RT_(cal)is equal to the length of the data-0 and data-1 symbol (i.e. RT_(cal) iswithin the time range form 2.5*Tari to 3.0*Tari).

Upon receiving a select command by a radio frequency identification(RFID) transponder, the transponder is instructed to reply on furthercommand. The first query command instructs the selected radio frequencyidentification (RFID) transponder to respond a 16-bit random orpseudo-random number (RN16). Upon reception of an acknowledgementcommand from the radio frequency identification (RFID) reader informingthe radio frequency identification (RFID) transponder that the 16-bitrandom or pseudo-random number (RN16) is valid, the transponder forinstance transmits an electronic product code (EPC), protocol control(PC) and a cyclic redundancy check (CRC) value. The radio frequencyidentification (RFID) reader is able to verify on the basis of thecyclic redundancy check whether the response is received successfully ornot. Accordingly, the radio frequency identification (RFID) reader maytransmit then a further command or a non-acknowledgement command. Thelatter command is transmitted to indicate to the radio frequencyidentification (RFID) transponder that the payload of the previousresponse has been received erroneously.

As indicated in FIG. 6 d, several waiting periods have to be consideredfor instance waiting periods between transmissions of consecutive radiofrequency identification (RFID) reader commands (T₄), between end of aradio frequency identification (RFID) reader command and start of theradio frequency identification (RFID) transponder response (T₁), and,vice versa, between end of the radio frequency identification (RFID)transponder response and start of a following radio frequencyidentification (RFID) reader command (T₂).

Commands and sequences of commands are provided to retrieve informationfrom radio frequency identification (RFID) transponders and/or to modifythe information stored at the radio frequency identification (RFID)transponders.

With reference to FIG. 6 e, a principle radio frequency identification(RFID) command sequence and radio frequency identification (RFID)transponder states are illustratively represented. The radio frequencyidentification (RFID) communication according to the EPCglobal standardis arranged for communication with a population of transponders, whichincludes in particular the communication with a single transponder.

The radio frequency identification (RFID) reader subsystem is enabled tomanage a population of radio frequency identification (RFID)transponders on the basis of three basic processes, which comprises inturn one or more process specific commands. The following descriptionbriefly described the basic processes without going into details.

A Select process is provided for choosing a population of radiofrequency identification (RFID) transponders for subsequentcommunication, in particular inventory and access command communication.A Select command may be applied successively to select a particularpopulation of radio frequency identification (RFID) transponders basedon user-specified criteria. This operation can be seen as analog toselecting one or more records from a database.

An Inventory process is provided fro identifying radio frequencyidentification (RFID) transponders, i.e. for identifying radio frequencyidentification (RFID) transponders out of the population chosen by themeans of the Select command. A radio frequency identification (RFID)reader subsystem may begin an inventory round, i.e. one or moreinventory command and transponder response cycles, by transmitting aQuery command in one of four sessions. One or more radio frequencyidentification (RFID) transponders may reply. The radio frequencyidentification (RFID) reader subsystem is enabled detecting a singleradio frequency identification (RFID) transponders reply and requestingthe PC, EPC, and CRC from the detected radio frequency identification(RFID) transponder. Inventory process may comprise multiple inventorycommands. An inventory round operates in one session at a time.

An Access process is provided for communicating with a radio frequencyidentification (RFID) transponder, where the communication comprisesespecially reading from and/or writing to the radio frequencyidentification (RFID) transponder. An individual radio frequencyidentification (RFID) transponders should be uniquely identified priorto the access process. The Access process may comprise multiple accesscommands, some of which employ one-time-pad based cover-coding of theReader to Transponder communication link.

In more detail, the Selection process employs a single command, Select,which a radio frequency identification (RFID) reader subsystem may applysuccessively to select a particular population of radio frequencyidentification (RFID) transponders based on user-defined criteria,enabling union, intersection, and negation based transponderpartitioning. The radio frequency identification (RFID) readersubsystems are enabled performing union and intersection operations byissuing successive Select commands.

The inventory process command set includes Query, QueryAdjust, QueryRep,ACK (acknowledgement), and NAK (non-acknowledgement) commands. The Querycommand initiates an inventory round and decides which radio frequencyidentification (RFID) transponders participate in the inventory round,where “inventory round” is defined as the period between successiveQuery commands. The Query command includes a slot-count parameter Q usedfor random back-off in the collision avoidance scheme. The slot-countparameter Q is configurable and settable by the radio frequencyidentification (RFID) reader subsystem. Upon receiving a Query command,each of the participating radio frequency identification (RFID)transponders should pick a random value in the range from 0 to 2^(Q)−1and should store this value into its slot counter. The radio frequencyidentification (RFID) transponders that pick a zero should transition tothe reply state and reply immediately. The radio frequencyidentification (RFID) transponders that pick a nonzero value shouldtransition to the arbitrate state and await a QueryAdjust or a QueryRepcommand. Assuming that a single radio frequency identification (RFID)transponder replies, the query-response algorithm provides the radiofrequency identification (RFID) transponder for backscattering a 16-bitrandom number or pseudo-random number (RN16) response as it entersreply. The radio frequency identification (RFID) reader subsystemacknowledges the radio frequency identification (RFID) transponder withan acknowledgment (ACK) command including this same RN16. Then, theacknowledged radio frequency identification (RFID) transpondertransitions to the acknowledged state, backscattering its PC, EPC, andCRC. Further, the radio frequency identification (RFID) reader subsystemmay issue a QueryAdjust or QueryRep command, causing the identifiedradio frequency identification (RFID) transponder to transition to readystate, and potentially causing another radio frequency identification(RFID) transponder to initiate a query-response dialog with the radiofrequency identification (RFID) reader subsystem, starting again theaforementioned query process sequence. If a radio frequencyidentification (RFID) transponder fails to receive the ACK command orreceives the ACK command with an erroneous RN16, the radio frequencyidentification (RFID) transponder should return to arbitrate state.

The radio frequency identification (RFID) transponders in arbitratestates or reply states that receive a QueryAdjust first adjust Q (byincrementing, decrementing, or leaving it unchanged), then pick a randomvalue in the range from 0 to 2^(Q)−1 and stores this value into theirslot counter. The radio frequency identification (RFID) transpondersthat pick zero should transition to the reply state and replyimmediately. The radio frequency identification (RFID) transponders thatpick a nonzero value should transition to the arbitrate state and awaita QueryAdjust or a QueryRep command. The radio frequency identification(RFID) transponders in the arbitrate state decrement their slot counterevery time they receive a QueryRep, transitioning to the reply state andbackscattering a RN16 when their slot counter reaches zero.

In summary, during RF activity cycle of the radio frequencyidentification (RFID) reader subsystem, first radio frequencyidentification (RFID) transponders are selects in accordance with theSelect process, afterwards the radio frequency identification (RFID)reader subsystem may proceed to Inventory process and last an Accessprocess by be executed.

Those skilled in the art will appreciate that the scheduler ispreferably enabled to obtain one or more of the aforementioned parametervalues and, if desired or required, to modify one or more of theparameter values. The scheduler obtains and/or modifies the parametervalues through the configuration and adjustment interface describedabove.

The scheduler may at least obtain and modify parameter values that arerelevant to aligning the RF activity of the radio frequencyidentification (RFID) reader subsystem and the cellular communicationsubsystem. The activity of the cellular communication subsystem isprioritized over the activity of the radio frequency identification(RFID) reader subsystem due to the fact that the activity of thecellular communication subsystem is typically under control of the RadioAccess Network (RAN) and the possibilities of the terminal to affect theactivity of the cellular communication subsystem is very limited.

Correspondingly, the available time periods and their timely distanceallowing radio frequency identification (RFID) communication are knownfrom the periods of activity and non-activity of the cellularcommunication subsystem. This means that maximum durations of individualcontinuous waves (CWs), refer to FIG. 6 d, and a sleep duration betweentwo consecutive continuous waves (CWs) is known. Within such maximumdurations, the radio frequency identification (RFID) communicationbetween reader subsystem and transponder(s) has to be performed, referto FIGS. 6 d and 6 e. The duration in time required for an envisagedradio frequency identification (RFID) communication procedure comprisingone or more commands and responses can be determined or estimated fromcommands and response sequence as well as the timing requirementsillustrated above. By adjusting one or more timing parameters includingin particular, reference time interval T_(ari), relative reference timeinterval value x, RF pulse width, carrier frequency, and slot-countparameter Q, the duration in time required for the envisaged radiofrequency identification (RFID) communication procedure can be optimizedin order to fit into a maximum duration of a single continuous wave(CW). The adjustment of the parameters should be at least possiblewithin one or more tolerance ranges. Upon setting of the digital (I/O)trigger signal, which substantially represent a Boolean parameter, theSelect process is started.

In addition, the RF power level of the radio frequency identification(RFID) reader subsystem may be adjusted on a corresponding power settingcommand issued by the scheduler to the radio frequency identification(RFID) reader subsystem. Moreover, the number of radio frequencyidentification (RFID) transponders to be read out may be defined orlimited.

It should be noted that the periods of non-activity of the cellularcommunication subsystem may be short in time in relationship to theduration in time required for a radio frequency identification (RFTD)communication in the way described above on the basis of the EPCglobalstandard for the way of illustration. The Reader-to-Transponder bit rateis within a range from 26.7 kbps to 128 kbps depending on the modulationscheme applied, whereas the Transponder-to-Reader bit rate within arange from 40 kbps to 640 kbps (and 5 kbps to 320 kbps when subcarriermodulate). However, the effective bit rate suffers from the severaltiming requirements for instance illustrated above with reference toFIG. 6 d. The period of non-activity available for radio frequencyidentification (RFID) communication should be used as effectively aspossible.

The radio frequency identification (RFID) communication and operation isprimarily described above in view of product tagging and identificationapplication. It should be understood that the invention is not limitedto any specific application and use case in the field of radio frequencyidentification (RFID) technology. In general, radio frequencyidentification (RFID) technology can be considered as a wireless storagetechnology, where transponders provide read-only and/or random accessstorage, which storage is wirelessly accessible by the means of readersubsystems. In principle, the communication between transponders andreader subsystem is operable in analogy to the illustrative embodiments.For instance, radio frequency identification (RFID) technology has beenselected for storing biometric identification information in digitallyenhanced passports. Such a passport comprises a radio frequencyidentification (RFID) transponder, which stores biometric informationabout the holder of the passport such as a digital image of his face, adigital representation of one or more finger prints, and/or a digitalrepresentation of an iris scan. Radio frequency identification (RFID)reader subsystems provided at passport control stations at a border of astate enable access to the stored biometric information to authenticatethe holder of the passport. In particular, the radio frequencyidentification (RFID) transponders in the passports implement accesscontrol mechanism to prevent unauthorized access to the storedinformation.

Moreover, radio frequency identification (RFID) transponder may be alsoprovided with sensor logic, especially condition monitoring sensors orenvironmental monitoring sensors such as temperature sensors, humiditysensors, pressure sensors, gas sensors (detecting one or more specifictypes of gas) and the like. The calibrating of such sensors and/or thereading access to these ones can be operated through the interface(s)described above in detail. However, it should to be considered that thecalibration access to a sensor implemented in a radio frequencyidentification (RFID) transponder requires a period in time, which willbe designated as a sensor reading period T_(read). The same applies tothe reading access of the data generated by such a sensor. The access tothe data generated by a sensor or obtained from a sensor requires aperiod in time, which will be designated as a sensor writing periodT_(write). Note that one or more sensor writing periods T_(qrite) andone or more sensor reading periods T_(read) should be also consideredwhen adjusting and/or optimizing of the operation of the radio frequencyidentification (RFID) reader subsystem. An optimization may be obtainedby limiting the number of sensor read and/or sensor write accesses,preferably to only one or more specific sensor per communication withthe radio frequency identification (RFID) transponder during a period ofnon-activity. In contrast to the above mentioned parameters which relateto communication properties (communication related parameters) thesensor related parameters can be designated in general as applicationrelated parameters.

According to yet a further embodiment of the present invention, theoperation of the radio frequency identification (RFFD) reader subsystemmay be employed to emitting a RF interrogation signal (RF excitationsignal, continuous wave) and, if necessary and/or required, forListen-Before-Talk measurement(s). The RF interrogation signal is forinstance (continuously) emitted to energize one or more radio frequencyidentification (RFID) transponders in the coverage area of the emittingradio frequency identification (RFID) reader subsystem. The datacommunication with the one or more radio frequency identification (RF1D)transponders (including data reception from the radio frequencyidentification (RFID) transponders as well as data and/or commandtransmission to the radio frequency identification (RFID) transponders)may be operated at a different radio frequency band, eventually alsowith a different protocol and/or on the basis of a different wirelessdata communication technology. However, the energy supply through a RFinterrogation signal is advantageous to enable provision of passivepowered module capable for wireless data communication.

Those skilled in the art will appreciate that the concept of the presentinvention described on the basis of a cellular communication subsystemis also applicable with other radio frequency communication subsystems,in particular wireless network interface subsystems. This means thatactivity scheduling of a radio frequency identification (RFID) readersubsystem according to an embodiment of the present invention should notbe limited to the aforementioned cellular communication subsystems, butthe overall solution is also applicable with the envisaged 3.9Generation and 4^(th) Generation Mobile Telephony Standards, WLAN(Wireless Local Area Network), WiMAX, UWB (Ultra-Wide Band), Bluetoothand any other wireless technologies. Though, the interference would beworst to wireless communication subsystem operating close to 900 MHz UHFband of the UHF radio frequency identification (RFID) subsystem, thewideband noise originating from the radio frequency identification(RFID) reader subsystem might cause also difficulties to wirelesscommunication subsystem operating at other frequencies of spectrum.

Moreover, the scheduling according to an embodiment of the presentinvention would be very beneficial with 2.4 GHz ISM radio frequencyidentification (RFID) reader subsystems, which would cause powerfulinterference to wireless communication subsystems operating at 2.4 GHzISM frequency band, e.g. IEEE 802.11b/g WLAN and Bluetooth.

On the basis of the inventive concept illustrated in accordance with thedescription above those skilled in the art will understand that asubstantially concurrent operation of a radio frequency identification(RFID) reader subsystem and a cellular/wireless communication subsystemis operable. Advantages of the substantially concurrent operation ofboth subsystems can be taken by the user when additional datacommunication is desired by the user for instance for retrievingadditional information in dependence of information retrieved from aradio frequency identification (RFID) transponder such as a dataretrieval in a data base storing such additional information. In view ofEPCglobal conform radio frequency identification (RFID) transponderwhich provides conventionally a preferably worldwide unique electronicproduct code (EPC), which serves as an identification code of the taggedproduct, the additional information may comprise for instance supplychain related information such as origin, manufacturer, wholesaler,manufacturing date, use-by date etc. Another use case may comprise thetransmission of the information read out from the radio frequencyidentification (RFID) transponder in a data base for supply chainmanagement purposes.

In contrast to the conventional way to first retrieve information formthe radio frequency identification (RFID) transponder, buffer theretrieved information, and after that perform the data base retrievalvia the cellular/wireless communication interface enabling wide areanetwork (WAN) accesses to for instance an Internet-based databaseservice, the inventive concept allows to omit buffering and acceleratesthe database retrieval due to substantially concurrent operation of bothsubsystems. Especially in the use case, where a multiplicity of radiofrequency identification (RFID) transponders are read out and the readout information may be stored in a data base or information may beretrieved form a data base in accordance with the read-out information,the advantages of the inventive concept are immediately apparent.

Moreover, the inventive concept addresses the operation of the radiofrequency identification (RFID) reader subsystem. Because of thetime-aligned operation of the subsystems, where the cellular/wirelesscommunication subsystem is typically prioritized due to network sideimplementations and requirements, the radio frequency identification(RFID) communication has to be adjusted to fit into the availableperiods of non-activity of the cellular/wireless communicationsubsystem. This fitting requirement can be achieved by adjusting one ormore parameters obtainable from the radio frequency identification(RFID) reader subsystem and adjustable for enabling matching in time ofthe radio frequency identification (RFID) communication with theavailable one or more periods of non-activity.

It will be obvious for those skilled in the art that as the technologyadvances, the inventive concept can be implemented in a broad number ofways. The invention and its embodiments are thus not limited to theexamples described above but may vary within the scope of the claims.

1. Method for scheduling communications over a wireless communicationsubsystem and a radio frequency identification communication subsystem;said method comprising: determining one or more periods of activity ofthe wireless communication subsystem; deriving one or more periods ofnon-activity on the basis of the one or more determined periods ofactivity; synchronizing an operation of the radio frequencyidentification communication subsystem with the one or more periods ofnon-activity; and triggering the operation of the radio frequencyidentification communication subsystem in accordance with the one ormore derived periods of non-activity to enable substantially concurrentcommunications operation of the wireless communication subsystem and theradio frequency identification communication subsystem.
 2. Methodaccording to claim 1, comprising: obtaining an operational state of thewireless communication subsystem, wherein the operational statecomprises at least an idle operation state and an active operationstate; and determining one or more periods of activity of the wirelesscommunication subsystem in dependence of the operational state. 3.Method according to claim 2, wherein the wireless communicationsubsystem is operative in the idle operation state; said methodcomprising: obtaining timing information relating to paging operationsand timing information relating to signal measurements from the wirelesscommunication subsystem; and determining periods of activity includingperiod lengths on the basis of the obtained timing information. 4.Method according to claim 2, wherein the wireless communicationsubsystem is operative in the active operation state; said methodcomprising: in case of time division multiple access-based wirelesscommunication subsystem: obtaining timing information about slot timingin accordance with time slots currently allocated to uplink and/ordownlink communications and measurement operations; and in case of acode division multiple access-based wireless communication subsystem:obtaining timing information about periods of activity in accordancewith a non-continuous communication mode.
 5. Method according to claim4, wherein said wireless communication subsystem is the time divisionmultiple access-based wireless communication subsystem; said methodcomprising: if applicable and/or required: requesting a time slotallocation for uplink and/or downlink communication which comprises oneor more unallocated time slots within a frame structure.
 6. Methodaccording to claim 4, wherein said wireless communication subsystem is awideband code division multiple access-based wireless communicationsubsystem; said method comprising: if applicable and/or required:requesting compressed frame communication mode; and obtaining timinginformation about transmission gaps and their lengths in accordance withthe compressed frame communication mode.
 7. Method according to claim 4,wherein said wireless communication subsystem is a cdma2000-basedwireless communication subsystem; said method comprising: if applicableand/or required: requesting discontinuous transmission mode; andobtaining timing information about the discontinuous transmission inreverse link and forward link.
 8. Method according to claim 1, saidmethod comprising: triggering the operation of the radio frequencyidentification communication subsystem in accordance with a ramp-upduration (Δ_(I)) and/or ramp-down duration (Δ_(III)) of the radiofrequency identification communication subsystem.
 9. Method according toclaim 1, said method comprising: obtaining one or more communicationand/or application related parameters of the radio frequencyidentification communication subsystem; and determining a communicationperiod required for an operation of the radio frequency identificationcommunication subsystem in accordance with the obtained communicationrelated parameters and/or application related parameters; and adjustingone or more communication related parameters and/or application relatedparameters of the radio frequency identification communication subsystemto adapt the communication period required for the operation of theradio frequency identification communication subsystem to the one ormore derived periods of non-activity.
 10. Method according to claim 9,wherein the communication related parameters of the radio frequencyidentification communication subsystem comprises one or more of thefollowing parameters including: a carrier sensing period (T_(LSB)); amodulation type including double sideband amplitude shift keying, singlesideband amplitude shift keying, and phase reversal amplitude shiftkeying; a reference time interval (T_(ari)) of a data-0 symbol; arelative reference time interval (x) of a data-1 symbol; a RF pulsewidth (PW); a carrier frequency; a slot-count parameter (Q); a RFenvelope rise time (T_(r)); a RF envelope fall time (T_(f)); a settlingtime (T_(s)); a time (T₁) from radio frequency identification commandtransmission to radio frequency identification transponder response; atime (T₂) from radio frequency identification transponder response toradio frequency identification command transmission; a time (T₃)representing a wait time upon missing radio frequency identificationtransponder response; and a minimum time (T₄) between successive radiofrequency identification command transmissions.
 11. Method according toclaim 9, wherein the application related parameters of the radiofrequency identification communication subsystem comprises one or moreof the following parameters including: a maximum number of sensoraccesses; a sensor reading time (T_(read)); and a sensor writing time(T_(write)).
 12. Method according to claim 1, said method comprising:determining a frequency band currently used by the wirelesscommunication subsystem; and in case the frequency band of the wirelesscommunication subsystem is such close to a frequency band used by theradio frequency identification communication subsystem that interferencehave to be expected: requesting for a frequency band handover of thewireless communication subsystem to a frequency band where interferencehave not to be expected; and enabling concurrent communicationsoperation of the wireless communication subsystem and the radiofrequency identification communication subsystem.
 13. Method accordingto claim 11, wherein the frequency band handover enables an operation ofthe wireless communication subsystem at another frequency band using asame protocol.
 14. Method according to claim 11, wherein the frequencyband handover comprises a protocol handover.
 15. Method according toclaim 1, said method comprising: lowering a RF signal power level of theradio frequency identification communication subsystem; and determiningan interference level; in case the interference level is below athreshold: enabling concurrent communications operation of the wirelesscommunication subsystem and the radio frequency identificationcommunication subsystem.
 16. Method according to claim 1, wherein theradio frequency identification communication subsystem is operable at anultra high frequency band, in particular at a frequency range from 860MHz to 960 MHz.
 17. Method according to claim 1, wherein the wirelesscommunication subsystem is operable with at least one out of a groupincluding a time division multiple access-based cellular wirelesscommunication subsystem and a code division multiple access-basedcellular communication subsystem.
 18. Method according to claim 16,wherein the wireless communication subsystem is operable with at leastone out of a group including a global system for mobile communication,GSM, cellular communication subsystem, a global system for mobilecommunication, GSM/general packet radio service, GPRS, cellularcommunication subsystem, a global system for mobile communication,GSM/enhanced data rates for global system for mobile communicationevolution, EDGE, cellular communication subsystem, a wideband codedivision multiple access-based cellular communication subsystem, and acdma2000 cellular communication subsystem.
 19. Computer program productcomprising program code sections stored on a machine-readable medium forcarrying out the operations of claim 1 to 13, when said program productis run on a processor-based device, a terminal device, a network device,a portable terminal, a consumer electronic device, or a wirelesscommunication enabled terminal.
 20. Scheduling module arranged forscheduling communications over a wireless communication subsystem and aradio frequency identification communication subsystem, wherein saidscheduling module is operable with the wireless communication subsystemand the radio frequency identification communication subsystem; whereinthe scheduling module is arranged for determining one or more periods ofactivity of the wireless communication subsystem and deriving one ormore periods of non-activity on the basis of the one or more determinedperiods of activity; wherein the scheduling module is synchronized withthe one or more periods of non-activity; and a trigger signal isgenerated by the scheduling module to trigger an operation of the radiofrequency identification communication subsystem in accordance with theone or more derived periods of non-activity to enable substantiallyconcurrent communications operation of the wireless communicationsubsystem and the radio frequency identification communicationsubsystem.
 21. Module according to claim 20, wherein the schedulingmodule is arranged for obtaining an operational state of the wirelesscommunication subsystem, which is operable with at least an idleoperation state and an active operation state, wherein the schedulingmodule is configured to determine one or more periods of activity of thewireless communication subsystem in dependence of the operational state.22. Module according to claim 21, wherein the wireless communicationsubsystem is operative in the idle operation state, wherein thescheduling module is arranged for obtaining timing information relatingto paging operations and timing information relating to signalmeasurements from the wireless communication subsystem, wherein thescheduling module is configured to determine periods of activityincluding period lengths on the basis of the obtained timinginformation.
 23. Module according to claim 21, wherein the wirelesscommunication subsystem is operative in the active operation state,wherein in case of a time division multiple access-based wirelesscommunication subsystem, the scheduling module is arranged for obtainingtiming information about slot timing in accordance with time slotscurrently allocated to uplink and/or downlink communications andmeasurement operations, wherein in case of a code division multipleaccess-based wireless communication subsystem, the scheduling module isarranged for obtaining timing information about periods of activity inaccordance with a non-continuous communication mode.
 24. Moduleaccording to claim 20, wherein the trigger signal is generated inaccordance with a ramp-up duration (Δ_(I)) and/or ramp-down duration(Δ_(III)) of the radio frequency identification communication subsystem.25. Module according to claim 20, wherein the scheduling module isarranged for obtaining one or more communication related parametersand/or application related parameters of the radio frequencyidentification communication subsystem and determining a communicationperiod required for an operation of the radio frequency identificationcommunication subsystem in accordance with the obtained communicationrelated parameters and/or application related parameters; wherein thescheduling module is configured to adjust one or more communicationrelated parameters and/or application relates parameters of the radiofrequency identification communication subsystem to adapt thecommunication period required for the operation of the radio frequencyidentification communication subsystem to the one or more derivedperiods of non-activity.
 26. Module according to claim 25, wherein thecommunication related parameters of the radio frequency identificationcommunication subsystem comprises one or more of the followingparameters including: a carrier sensing period (T_(LSB)); a modulationtype including double sideband amplitude shift keying, single sidebandamplitude shift keying, and phase reversal amplitude shift keying; areference time interval (T_(ari)) of a data-0 symbol; a relativereference time interval (x) of a data-1 symbol; a RF pulse width (PW); acarrier frequency; a slot-count parameter (Q); a RF envelope rise time(T_(r)); a RF envelope fall time (T_(f)); a settling time (T_(s)); atime (T₁) from radio frequency identification command transmission toradio frequency identification transponder response; a time (T₂) fromradio frequency identification transponder response to radio frequencyidentification command transmission; a time (T₃) representing a waittime upon missing radio frequency identification transponder response;and a minimum time (T₄) between successive radio frequencyidentification command transmissions.
 27. Module according to claim 25,wherein the application related parameters of the radio frequencyidentification communication subsystem comprises one or more of thefollowing parameters including: a maximum number of sensor accesses; asensor reading time (T_(read)); and a sensor writing time (T_(write)).28. Module according to claim 20, wherein the scheduling module isarranged for determining a frequency band currently used by the wirelesscommunication subsystem, wherein in case the frequency band of thewireless communication subsystem is such close to a frequency band usedby the radio frequency identification communication subsystem thatinterference have to be expected, the scheduling module is configured torequest for a frequency band handover of the wireless communicationsubsystem to a frequency band where interference have not to beexpected, wherein the frequency band handover enables concurrentcommunications operation of the wireless communication subsystem and theradio frequency identification communication subsystem.
 29. Moduleaccording to claim 20, wherein the scheduling module is configured tolower a RF signal power level of the radio frequency identificationcommunication subsystem and determine an interference level such that incase the interference level is below a threshold: concurrentcommunications operation of the wireless communication subsystem and theradio frequency identification communication subsystem is enabled. 30.Terminal device enabled for scheduled communications over a wirelesscommunication subsystem and a radio frequency identification (RFID)communication subsystem of the terminal device, wherein the terminaldevice comprises a scheduling module operable with the wirelesscommunication subsystem and the radio frequency identificationcommunication subsystem; wherein the scheduling module is arranged fordetermining one or more periods of activity of the wirelesscommunication subsystem and deriving one or more periods of non-activityon the basis of the one or more determined periods of activity; whereinthe scheduling module is synchronized with the one or more periods ofnon-activity; and a trigger signal is generated by the scheduling moduleto trigger an operation of the radio frequency identificationcommunication subsystem in accordance with the one or more derivedperiods of non-activity to enable substantially concurrentcommunications operation of the wireless communication subsystem and theradio frequency identification communication subsystem.
 31. Deviceaccording to claim 30, wherein the scheduling module is a schedulingmodule arranged for obtaining an operational state of the wirelesscommunication subsystem, which is operable with at least an idleoperation state and an active operation state, wherein the schedulingmodule is configured to determine one or more periods of activity of thewireless communication subsystem in dependence of the operational state.32. Device according to claim 30, wherein the wireless communicationsubsystem and the radio frequency identification communication subsystemare operable with a common antenna, which radio frequency characteristicis adapted to operating frequencies of the subsystems.
 33. Deviceaccording to claim 30, wherein the trigger signal is generated uponsignalization from an application executable at the device and/or uponreception of an input signal originating from a user input.
 34. Deviceaccording to claim 30, wherein the terminal device is a cellularterminal device capable for multi frequency band and/or multi systemcellular communications.
 35. Device according to claim 34, wherein thewireless communication subsystem is operable with at least one out of agroup including a time division multiple access-based cellular wirelesscommunication subsystem and a code division multiple access-basedcellular communication subsystem.
 36. Device according to claim 35,wherein the wireless communication subsystem is operable with at leastone out of a group including a global system for mobile communication,GSM, cellular communication subsystem, a global system for mobilecommunication, GSM/general packet radio service, GPRS, cellularcommunication subsystem, a global system for mobile communication,GSM/enhanced data rates for global system for mobile communicationevolution, EDGE, cellular communication subsystem, a wideband codedivision multiple access-based cellular communication subsystem, anuniversal mobile telecommunications system, UMTS, cellular communicationsubsystem, and a cdma2000 cellular communication subsystem.
 37. Deviceaccording to claim 30, wherein the wireless communication subsystem is awireless network interface subsystem, wherein the wireless networkinterface subsystem is operable with at least one out of a groupincluding IEEE 802.xx wireless network communication technology,Bluetooth wireless communication technology, and ultra-wide bandwireless network communication technology.
 38. System enabling scheduledcommunications over a cellular communication subsystem and a radiofrequency identification communication subsystem, wherein the systemcomprises a scheduling module operable with the cellular communicationsubsystem and the radio frequency identification communicationsubsystem; wherein the scheduling module is arranged for determining oneor more periods of activity of the cellular communication subsystem andderiving one or more periods of non-activity on the basis of the one ormore determined periods of activity; wherein the scheduling module issynchronized with the one or more periods of non-activity; and a triggersignal is generated by the scheduling module to trigger an operation ofthe radio frequency identification communication subsystem in accordancewith the one or more derived periods of non-activity to enablesubstantially concurrent communications operation of the cellularcommunication subsystem and the radio frequency identificationcommunication subsystem.
 39. System according to claim 38, wherein thescheduling module is a scheduling module arranged for obtaining anoperational state of the wireless communication subsystem, which isoperable with at least an idle operation state and an active operationstate, wherein the scheduling module is configured to determine one ormore periods of activity of the wireless communication subsystem independence of the operational state.
 40. System according to claim 38,further comprising a terminal device that comprises the schedulingmodule.
 41. System according to claim 38, wherein the wirelesscommunication subsystem and the radio frequency identificationcommunication subsystem are operable with a common antenna, which radiofrequency characteristic is adapted to operating frequencies of thesubsystems.
 42. System according to claim 38, wherein the radiofrequency identification communication subsystem is at least operable atan ultra high frequency band, in particular at a frequency range from860 MHz to 960 MHz.
 43. System according to claim 42, wherein the radiofrequency identification communication subsystem is operable with EPCGlobal standard.
 44. System according to claim 38, wherein the radiofrequency identification communication subsystem is operable at an ISMfrequency band, in particular at a 2.4 GHz ISM frequency band.